Herbal Support for Methicillin-Resistant Staphylococcus aureus Infections

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DOI: 10.1089/act.2009.15402
Cite this publication
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a modern plague of growing proportions. Herbal medicine offers two potential solutions to this major health issue. First, in some cases, herbs may be substituted for antibiotics altogether. This approach reduces antibiotic use and thus helps prevent worsening of antibiotic resistance, while still controlling the MRSA. Second, herbs can augment the effect of antibiotics and even overcome drug resistance when antibiotics are appropriate and necessary.
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189
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a
modern plague of growing proportions. Herbal medicine of-
fers two potential solutions to this major health issue. First,
in some cases, herbs may be substituted for antibiotics alto-
gether. This approach reduces antibiotic use and thus helps
prevent worsening of antibiotic resistance, while still control-
ling the MRSA. Second, herbs can augment the effect of an-
tibiotics and even overcome drug resistance when antibiotics
are appropriate and necessary.
This article discusses herbs that potentially have these
benefits: The herbs include Camellia sinensis (green tea)
leaf, Theobroma cacao (chocolate) fruit, Melaleuca alternifo-
lia (tea tree) leaf essential oil, Pelargonium sidoides (African
geranium) essential oil, Cymbopogon flexuosus (lemongrass)
essential oil, Thymus capitatus (thyme) flowering top essen-
tial oil, Lavandula spp. (lavender) essential oil, Panax gin-
seng (Asian ginseng) root, Panax quinquefolius (American
ginseng) root, Geranium caespitosum (pineywoods geranium)
herb, Rosmarinus officinalis (rosemary) leaf and essential
oil, Lycopus europaeus (bugle weed) herb, Santalum spicatum
(Australian sandalwood), Origanum vulgare (oregano) herb
essential oil, Allium sativum (garlic) bulb, Mahonia aquifo-
lium (Oregon grape) root, Hypericum perforatum (St. John’s
wort) herb, Bursera microphylla (elephant tree) resin, Com-
miphora molmol (myrrh) resin, Cinnamomum zeylanicum (true
cinnamon) bark volatile oil, Echinacea angustifolia (echinacea)
root, Quercus spp. (oak) bark, Anemopsis californica (yerba
mansa) root, Usnea spp. (old man’s beard) thallus, Juniperus
communis (juniper) fruit, Larrea tridentata (chaparral) herb,
Glycyrrhiza glabra (licorice) root, Zingiber officinale (ginger)
rhizome, and Syzygium aromaticum (clove) volatile oil.
Introduction
Methicillin-resistant Staphylococcus aureus (MRSA), a seri-
ous infection, is occurring more frequently. Despite the focus
on the resistance of this organism to methicillin, the reality is
that it is a multidrug-resistant infection. Because of the on-
going, nearly indiscriminate use of broad-spectrum antibiotics
and presence of low doses of these antibiotics in animal feed,
MRSA and, even worse, antibiotic-resistant infections will
continue to be a major problem. The use of ever more potent
antibiotics in conventional medicine is causing the emergence
of even more drug-resistant MRSA (such as the upcoming
plague of vancomycin-resistant S. aureus).
Herbal medicine offers two potential ways out of this trap.
First, in some cases, herbs may be substituted for antibiotics
altogether. This reduces antibiotic use and thus helps prevent
worsening of antibiotic resistance while still controlling the
MRSA. Second, herbs can be used to augment the effect of
antibiotics and even overcome drug resistance, particularly by
blocking efflux pumps, when they are absolutely necessary. This
article discusses herbs that potentially have these benefits.
The Biology of MRSA
This dangerous strain of organism has attained methicillin
resistance and thus carries the MRSA moniker. Methicillin re-
sistance in penicillin-resistant S. aureus was documented with-
in 2 years of the introduction of methicillin in 1959.1 MRSA
is unlike many other prior antibiotic-resistant infections in
that it occurs more often in the community in people with
no exposure to health care institutions.2 Many studies have
confirmed that MRSA infections have higher rates of mortal-
ALTERNATIVE AND COMPLEMENTARY THERAPIES DOI: 10.1089/act.2009.15402 • MARY ANN LIEBERT, INC. • VOL. 15 NO. 4
AUGUST 2009
Herbal Support for
Methicillin-Resistant
Staphylococcus aureus
Infections
Eric Yarnell, N.D., and
Kathy Abascal, B.S., J.D., R.H. (AHG)
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Proposed Comprehensive Approach to MRSA
For mild or early cutaneous MRSA infections
1. Apply multiple topical antimicrobial herbs, usually essential oils, although creams or ointments are also appropriate, in a base of
honey.*,
A sample topical volatile oil formula includes:
• Melaleuca alternifolia(teatree),25%
• Santalum spicatum(Australiansandalwood),25%
• Origanum vulgare(oregano),25%
• Rosmarinus officinalis(rosemary),20%
• Pogostemon patchouli(patchouli),5%(base/absorptionenhancer).
Instruct the patient to apply 3–5 drops over the affected area 2–3 times per day and cover with honey and a bandage. An antibacterial
cream formula should include a base cream of Allium sativum(garlic),30mL.Addthefollowingtincturestothecream:
• Mahonia aquifolium(Oregongrape)root,5mL(antimicrobial)
• Hypericum perforatum(St.John’swort)herb,5mL(antimicrobial)
• Camellia sinensis(greentea)leaf,5mL(resistancemodulator)
• Bursera microphylla(elephanttree)resin,5mL(antimicrobial).
If these herbs are not available, substitute Commiphora molmol(myrrh)resin,5mL,andCinnamomum zeylanicum(truecinnamon)bark
 volatileoil,5drops(antimicrobial).Instructthepatienttoapplythecreamliberallyoveraffectedarea3–5timesperdayandcoverwith
honey and a bandage.
2. Instruct the patient to eat a minimum of 3 fresh cloves of garlic per day.
3. Instruct the patient to take an immune stimulator orally, such as Echinacea angustifolia(echinacea)roottincture,3–5mlt.i.d.ormoreoften.
4.Instructthepatienttodrinkplentyofwater,avoidallsugar,eathealthyfoodslightly,getsunshine(including,ifpossible,directlyonthe
affected area, being careful not to cause a sunburn), and rest/reduce stress.
For more serious cutaneous MRSA infections
1. Apply topical antimicrobial herbs as stated for milder infections. Consider instructing the patient to apply these more frequently or to
use more than one type of application interchangeably.
2. Quercus spp.(oak)barkpoulticeorfomentationapplied2–3timesperdayfor30–60minutestothewound,betweenapplicationsof
other topical treatments.#,||
3. Instruct the patient to take a high-dose antimicrobial herbal formula internally. A sample spicy MRSA formula includes:
• Anemopsis californica(yerbamansa)roottincture,25%
• Usneaspp.(oldman’sbeard)thallustincture,20%
• Juniperus communis(juniper)fruittincture,15%
• Larrea tridentata(chaparral)herbtincture,10%
• Propolisresintincture,10%
• Glycyrrhiza glabra(licorice)rootfluidextract,10%**
• Zingiber officinale(ginger)rhizometincture,10%
• Syzygium aromaticum(clove)volatileoil,10drops.
Instruct the patient to take 5 mL of this formula every 2–4 hours,
4. Instruct the patient to eat at least 5–10 fresh cloves of garlic per day.
5. Tell the patient to follow all other directions under mild cutaneous infections above.
For internal MRSA infections
1. Tell the patient to follow the directions for serious cutaneous infections but leave out any topical applications. If the patient is also on
antibiotics, in addition to the recommendations above, tell him or her to drink 5–10 cups of green tea per day and/or eat 2–4 oz of dark
chocolateperdaybutnottoconsumethesewithin1hourofintakeoforalantibiotics.Explainthatthisprecautionistoavoidasmall
risk of decreased absorption of the drug that results from the tannins in these medicinal plants. Advise the patient also to take at least
50 billion organisms of probiotics per day and eat fermented foods.
*BlaserG,SantosK,BodeU,etal.EectofmedicalhoneyonwoundscolonisedorinfectedwithMRSA.JWoundCare2007;16:325–328.
CooperRA,MolanPC,HardingKG.Thesensitivitytohoneyofgram-positivecocciofclinicalsignicanceisolatedfromwounds.JApplMicrobiol2002;93:857–863.
Nostro A, Blanco AR, Cannatelli MA, et al. Susceptibility of methicillin-resistant staphylococci to oregano essential oil, carvacrol and thymol. FEMS Microbiol Lett
2004;230:191–195.
LuoMF,ShenQ,ZhangT,XuYH.Eectofatractylodesrhizomeoilandothervolatileoilsonpercutaneousabsorptionofbaicalin[inChinese].ZhongYaoCai2008;31:1721–1724.
#DavisSC, MertzPM.Determiningthe eectof anoak barkformulation onmethicillin-resistant Staphylococcus aureus and wound healing in porcine wound models. Ostomy
WoundManage2008;54:16–8,20,22–25.
||Chusri S, Voravuthikunchai SP. Quercus infectoria: A candidate for the control of methicillin-resistant Staphylococcus aureusinfections.PhytotherRes2008;22:560–562.
**LeeJW,JiYJ,YuMH,etal.AntimicrobialeectandresistantregulationofGlycyrrhiza uralensis on methicillin-resistant Staphylococcus aureus. Nat Prod Res 2009;23:101–111.
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ity, cost more to treat, and result in longer hospital stays than
other S. aureus infections.3 Despite the notoriety of the rise of
MRSA and supposed health care responses to the problem, the
rate of infection continues to increase.4
Unlike penicillin resistance, which is mediated by b-lacta-
mase that degrades the antibiotic, methicillin resistance results
from production of penicillin-binding proteins 2 and 2A me-
diated by the gene mecA.5 These proteins allow the microbe to
avoid not just b-lactamase–resistant methicillin but also stan-
dard penicillins, cephalosporins, and carbapenems. Different
types of mecA are associated with community-acquired (types
IV–V) versus hospital-acquired infections (types I–III).6
There has been little to no real effort to address the underlying
causes of MRSA, which, like other forms of antibiotic resistance,
are due in part to the result of antibiotic use.7–9 Another huge, and
still largely ignored, problem is the feeding of the same antibiotics
used therapeutically in humans to animals in low doses to pro-
mote growth. Recently, this has been linked directly to outbreaks
of drug-resistant infections in humans.10 So, ultimately, MRSA
will only be solved by vastly reducing use of antibiotics, particu-
larly removing them from animal feed and decreasing ongoing
routine use of antibiotics for patients with viral upper–respiratory
tract infections (URIs) that do not respond to these drugs.11
Each new antibiotic that has been put forward to treat
MRSA infections has resulted in rapid development of resis-
tance to that antibiotic. Linezolid came out in 2000, and with-
in a year, MRSA resistance to this drug was reported.12 Dap-
tomycin came out in 2003, and by 2005, resistance to this was
reported.13 Vancomycin resistance has already been increasing
in MRSA.14,15 All of these reports suggest that the approach
of simply using new antibiotics will not address MRSA, but
only ultimately breed an even more powerful and dangerous
problem. Herbs offer an alternative.
Clinical Aspects of MRSA
MRSA can infect tissues all over the body, including
skin, muscle, joints, and various organs. Most community-
acquired cases are in skin or soft tissue, although there is
a growing number of invasive infections.16 MRSA should
be suspected with new-onset inflammatory skin lesions, in-
cluding impetigo, folliculitis, and furunculosis, that are very
severe or therapy resistant. Patients with rapidly spreading
infections, or those associated with systemic symptoms such
as weakness, fever, myalgia, and/or anorexia, should be re-
ferred to an emergency (ER) room to avoid the risk of sepsis
or invasive infection.
There is some indication that patients who have taken anti-
biotics, who have recent trauma, who have recently been hos-
pitalized, who work in health care, or who are in other institu-
tional settings in which infections readily spread (e.g., daycare
centers, nursing homes, or locker rooms) are at higher risk of
MRSA infections.
Green Tea
Camellia sinensis (green tea) leaf and extracts thereof act in
multifaceted ways against MRSA. Green tea is also one of the
few herbs that has been subjected to an actual clinical trial
suggesting synergy with antibiotics in humans infected with
MRSA. A case study originally suggested that aerosolized
green tea could help resolve severe MRSA infections, in this
situation, one involving the trachea.17
In a randomized preliminary trial, 24 elderly Japanese pa-
tients with MRSA in their sputum were given either 2 mL
of a solution of green-tea catechins (with a concentration of
3.7 g/L) three times daily by nebulizer for 4 weeks, or mixed
into saline and bromhexine on a similar dose schedule.18 It was
unclear whether these patients were all being simultaneously
treated with antibiotics. MRSA clearance was significantly
greater in the green-tea group, and the subjects in this group
were also able to leave the hospital significantly sooner than
those in the control group. No adverse effects occurred.
This study was followed by a larger randomized trial of
similar design involving 72 disabled, elderly Japanese patients
with MRSA in their sputum.19 After 1 week of treatment, sig-
nificantly more patients in the green-tea group had reduced
or cleared MRSA from their sputum than the patients in
the control group (17/36 versus 5/33). Again, it was unclear
whether these patients were simultaneously taking antibiotics.
No adverse effects occurred in this trial. While clearly these
trials are not completely definitive, they do suggest that nebu-
lized green tea is a potentially safe way to help people with
respiratory MRSA infections.
Green tea acts in many different ways against MRSA. Sev-
eral green tea compounds show a range of resistance-modu-
lating effects. Epigallocatechin gallate (EGCG) has inhibited
b-lactamase in vitro and was synergistic with various b-lactam
antibiotics.20 Methicillin would not necessarily be needed if
the underlying resistance of MRSA to older penicillin-type
drugs was addressed.
Combined with oxacillin in vitro, epicatechin gallate (ECG)
from green tea markedly lowered the minimum inhibitory con-
centration (MIC) of the antibiotic against MRSA.21,22 The
gallate moiety of various polyphenols in green tea was deter-
mined to be essential for inhibiting b-lactamase and reversing
antibiotic resistance in MRSA in vitro.23 EGCG also lowered
the MIC of MRSA to ampicillin and sulbactam to the point
that resistance to these drugs was abrogated.24 EGCG has also
been shown to lower the MIC of imipenem, panipenem, and
meropenem against MRSA to the point that it became sensi-
tive to these drugs.25
Ultimately, MRSA will only be
solved by vastly reducing use
of antibiotics.
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Green tea blocks efflux pumps that normally remove vari-
ous antibiotics from MRSA. For example, EGCG inhibited
tetracycline efflux from staphylococci by way of the Tet(K) and
Tet(B) pumps.26 EGCG was active at concentrations more
than half its own MIC of 100 mcg/mL. Caution is warranted
if green tea is combined with glycopeptide antibiotics such as
vancomycin, as one in vitro trial suggested purified EGCG
could directly interfere with the action of these drugs.27
Green tea, EGCG, and theaflavin also produce inher-
ent, direct, antimicrobial activity against MRSA.28 EGCG
has been reported to disrupt cell-wall components and in-
hibit DNA gyrase in S. aureus in vitro.29,30 EGCG inhib-
its staphylococcal gelatinase, an enzyme it uses to spread
through tissues, and thus green tea may also limit micro-
bial invasiveness.31 EGCG is removed from many bacterial
cells by the multidrug resistance (MDR) pump, however,
which limits EGCG’s antimicrobial activity.32 (Note: The
exact same pump is present in other bacteria and cancer
cells.) Some researchers might argue that this would make
EGCG as an isolated constituent that is useless or doomed
to the same fate as single molecular entity antibiotic drugs.
However, catechin gallate in whole green tea inhibits MDR
and could be expected to preserve at least some of EGCG’s
activity.33 This inhibition could also reduce multidrug re-
sistance in bacteria in general, thus enhancing the efficacy
of antibiotics.
It has been observed that, when EGCG oxidizes—which
it does rapidly in most solutions regardless of pH—it loses
activity. The combination of vitamin C with EGCG in vitro
enhanced the antibacterial and resistance-modulating activi-
ties of EGCG against MRSA.34 It should be noted that intact
green tea is naturally fairly rich in vitamin C, arguing for the
synergy of using the whole plant. However, other research has
shown that EGCG oxidation products, particularly the major
one known as theasinensin A, do still have resistance-modulat-
ing effects against MRSA.35
Green tea, given all these advantages, should be strongly
considered in the protocol for any patient with a MRSA in-
fection. The herb can be delivered as an infusion (1–5 g/cup
of water, several cups/day), powder in capsules (10–15 g/day),
topically in cream or ointment, or by nebulization of infusion
or extracts dissolved in water.
Dark Chocolate
One alternative to green tea is Theobroma cacao (chocolate),
as it contains significant levels of EGCG and other important
molecules found in tea. Some research suggests that chocolate
is even richer in these molecules than green tea.36 Therefore, it
is reasonable to consider 2–4 oz of dark chocolate (at least 60%
cocoa solids, but probably greater than 75% would be ideal)
per day as a way to reduce antibiotic resistance in MRSA at
the very least. This chocolate should not be taken at the ex-
act same time as the antibiotics, as chocolate’s tannins might
interfere with absorption of the antibiotics. We have seen this
approach to be effective in at least one case of a patient with
recurrent cellulitis of the legs, at least some instances of which
were strongly suspected of being a result of MRSA (the patient
did not have sufficient resources to afford cultures to verify
this). Previously, dicloxacillin had not worked on some occa-
sions when this patient took it alone, but it worked when the
patient took it with dark chocolate.
Tea Tree and Other Volatile Oils
A more directly antimicrobial approach to MRSA, using
natural products, emphasizes volatile oils. These highly con-
centrated (more than 1000 times more concentrated than in
the crude herb) extracts were historically made by steam distil-
lation and so contain compounds altered by heat. Newer su-
percritical carbon-dioxide extracts are not altered by heat and
cannot be said to be equivalent to steam-distilled oils, although
these extracts may still be very appropriate for use.
Melaleuca alternifolia (tea tree) leaf from Australia provides
a powerful volatile oil that has the most clinical and preclini-
cal research in this category. A major issue with MRSA is that
some people act as asymptomatic carriers of the organism,
Green tea should be strongly
considered in the protocol for any
patient with a MRSA infection.
Theobroma cacao(chocolate) fruit.Drawing© 2009byKathyAbascal,J.D.,
R.H.(AHG).
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spreading it to other susceptible people or setting themselves
up for recurrent infections.
In a randomized trial, 114 hospital patients who were MRSA
carriers were treated with standard antimicrobials (mupirocin
2% intranasal ointment, chlorhexidine soap, and silver sulfa-
diazine ointment) and compared with 110 patients treated
with 10% tea tree cream intranasally and a 5% tea tree oil body
wash.37 Both groups were treated for 5 days. Both treatment
regimens were equally effective for reducing MRSA carriage.
Mupirocin was significantly more effective than tea tree oil for
clearing nasal carriage.
Tea tree oil at a 5% concentration is bactericidal against
biofilms of MRSA in vitro.38 Topical tea tree combined with
Pelargonium sidoides (African geranium) volatile oil infused
into a multilayered wound dressing produced strong anti-
MRSA activity in vitro.39 However, when MRSA in culture is
habitually exposed to sublethal concentrations of tea tree oil, it
becomes increasingly resistant to it.40 Unfortunately, this also
appears to raise the resistance of the organism to other anti-
biotics, including mupirocin, which is frequently used to treat
MRSA infections or to eliminate carriage of the organism.41
The current trend toward putting antimicrobial volatile oils in
soap, hand lotion, and other products is, therefore, not a particu-
larly good idea, as it is very likely that these oils will simply lead
to development of resistance in bacteria just as has been seen
with isolated chemicals. These data also strongly suggest that
only medicinal doses of tea tree oil should be delivered, and only
for as long as necessary, to avoid the development of resistance.
Full-strength, or as minimally diluted as possible (to toler-
ance), tea tree oil applied topically several times a day to MRSA
skin infections is recommended. On sensitive tissues, tea tree
oil should be diluted with jojoba or some other hypoallergenic
carrier by at least 50%. Internally 2–5 drops of tea tree oil can
be taken 4–5 times per day by people with normal liver and
kidney function as part of an anti-MRSA protocol.
Some other volatile oils that have shown anti-MRSA activity
in vitro and that might be appropriate to combine with tea tree
oil include African geranium mentioned above, Cymbopogon
flexuosus (lemongrass), Thymus capitatus (thyme)—especially
from flowering tops—and Lavandula spp. (lavender).42–44 All
of these can be used topically and internally in similar doses to
tea tree. All volatile oils are very concentrated and potentially
dangerous and should be used with caution and only by prac-
titioners trained in their use.
Resistance Modulators
In some cases, antibiotics are required because of the severity
of the MRSA infection. In these situations, certain herbs are
used in combination with antibiotics to enhance their efficacy
and directly reduce antibiotic resistance. Green tea and choco-
late have already been mentioned as excellent choices for this
kind of treatment. A few recently researched herbs are specific
to MRSA, although we have more-extensively reviewed the
data on antimicrobial resistance modulators elsewhere.45
Ginsenosides from Panax ginseng (Asian ginseng) root have
been mildly antistaphylococcal in vitro (MIC 100 mcg/mL)
and significantly synergistic with cefotaxime and kanamycin
against MRSA strains (reducing their MICs 2–20-fold).46
Given Asian ginseng’s positive effects on the immune sys-
tem, this herb might offer additional benefits. This effect has
been demonstrated with a close cousin, Panax quinquefolius
(American ginseng), an extract of the root that helps prevent
colds and flus.47 Each of these herbs has a long history of use
and is reasonable to consider for treating patients who have
MRSA infections. A typical dose is 1–3 g of powdered root
three times per day or 3–5 mL of tincture three times per day.
Trials should be done to determine the immune and resistance
modulating-effects of Asian and American ginseng in patients
with MRSA.
Geranium caespitosum (pineywoods geranium) contains com-
pounds that appear to inhibit NorA efflux pumps in MRSA.48
These compounds (at concentrations under 6.25 mcg/mL) po-
tentiate the activity of quinolone antibiotics such as ciprofloxacin
as well as the natural antimicrobial compounds berberine and
rhein against S. aureus in vitro. Many other species of geranium
with similar chemistry exist and thus might also be useful.
Rosmarinus off icinalis (rosemary) leaf, in particular its diterpe-
noids, has inhibited multiple antibiotic efflux pumps in MRSA
strains in vitro including erythromycin and NorA multidrug
pumps.49 In another study, researchers were not able to demon-
strate antibiotic–rosemary synergy in vitro, and in fact, showed
that rosemary lowered the efficacy of ciprofloxacin.50 The MICs
noted by these researchers were also radically different from those
mentioned in other literature (60 versus < 5 mg/mL).51
Reconciling this wildly different study with others is dif-
ficult at best. Most other studies show that rosemary produces
significant inherent antimicrobial activity of its own, includ-
ing against staphylococcal species.52 A nonantimicrobial rela-
tive in the same family (Lamiaceae), Lycopus europaeus (bugle
weed) herb has similar pump-inhibiting diterpenoids as rose-
mary. Extracts of this herb effectively lower the MIC of vari-
ous antibiotics against MRSA in vitro.53, 54
Garlic
Another antimicrobial food/herb recommended by many
practitioners for patients with MRSA infections is Allium
sativum (garlic) bulb. There is substantial evidence in the
literature that garlic bulb can directly kill MRSA, at least
this effect has been seen in vitro and in mice.55,56 No clinical
Putting antimicrobial volatile oils in
soap, hand lotion, and other products
is not a particularly good idea
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trials are yet available. A typical recommendation is for a pa-
tient with a MRSA to eat 5–10 fresh cloves of garlic per day.
This may be intolerable to some people, but lower doses are
not sufficient for such a severe infection. Patients should be
cautioned that cooking garlic reduces its antimicrobial prop-
erties significantly.
Conclusion
Research on herbs to prevent or treat MRSA infection is a
burgeoning field with many promising early results. Besides
having their own intrinsic activity, herbs also offer interesting
possibilities when combined with antibiotics to restore activ-
ity.54 While much more research is needed, clinicians do now
clearly have some natural options to add to their approach to
infections with this dangerous organism. n
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Eric Yarnell, N.D., is president of the Botanical Medicine Academy, a spe-
cialty board for using medicinal herbs, and is a faculty member at Bastyr
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com or call (914) 740-2100.
15_4ACT.indd 195 8/6/09 12:53:23 PM
  • ... El-Lati,Sacaan, Suleiman, & Amin, 1987;Takaki et al., 2008), expectorant (Takaki et al., 2008), food additive (animal feed) (Cross, Acamovic, & McDevitt, 2004aCross, McDevitt, Hillman, & Acamovic, 2007;Hernandez, Madrid, Garcia, Orengo, & Megias, 2004), food preservative (Ayadi, Grati-Kamoun, & Attia, 2009;Soler-Rivas et al., 2010), gout, and halitosis (Frackowiak, Fiszer-Kuc, Maliszewska, Bruziewicz-Mikla-Szewska, & Gancarz, 2003), headache (Yarnell & Abascal, 2007), hepatoprotection (Amin & Hamza, 2005;Fahim, Esmat, Fadel, & Hassan, 1999;Hoefler, Fleurentin, Mortier, Pelt, & Guillemain, 1987;Kitano et al., 2000;Sotelo-Felix et al., 2002b), herpes labialis (Reichling, Nolkemper, Stintzing, & Schnitzler, 2008), HIV infection, hypercholesterolemia, and hyperglycemia (Kwon, Vattem, & Shetty, 2006;Rau et al., 2006), hypertension (Kwon et al., 2006), hyperthyroid (Yarnell & Abascal, 2006), immunostimulation, and infections (drug-resistant) (Luqman, Dwivedi, Darokar, Kalra, & Khanuja, 2007), ischemic heart disease, joint pain, and lice (Veal, 1996), liver cirrhosis (Harach et al., 2009;Kaziulin, Petukhov, & Kucheriavyi, 2006;Vitaglione, Morisco, Caporaso, & Fogliano, 2004), memory enhancement, and metabolic disorders (bone) (Putnam, Scutt, Bicknell, Priestley, & Williamson, 2007), methicillin-resistant Staphylococcus aureus (MRSA) (Quave, Plano, Pantuso, & Bennett, 2008;Yarnell & Abascal, 2009), muscle relaxant (smooth muscle), and nerve regeneration (Hsieh et al., 2007), obesity (Harach et al., 2009;Lee et al., 2007;Takahashi et al., 2009), osteoporosis (Muhlbauer, Lozano, Palacio, Reinli, & Felix, 2003;Putnam et al., 2007), paralysis, and Parkinson's disease (sporadic) (Park et al., 2008), peptic ulcer (Dias, Foglio, Possenti, & de Carvalho, 2000;Mahady et al., 2005), peripheral vascular disease, and photoprotection (Hsu, 2005;Lee et al., 2007;Martin et al., 2008;Offord, Mace, Ruffieux, Malnoe, & Pfeifer, 1995), poor circulation, and psychiatric disorders (Aleisa, 2008), quality of life, renal colic, and respiratory disorders (Rakover, Ben Arye, & Goldstein, 2008), skin care (Baumann, 2007;Calabrese et al., 2000Calabrese et al., , 2001), skin conditions (excessive oil secretion and cellulite), sperm motility, and stomach ulcers caused by Helicobacter pylori bacteria (Matsubara et al., 2003), tonic, and toxicity (dieldrin-induced neurotoxicity) (Park et al., 2008), wound healing (Hsu, 2005), and wrinkle prevention. ...
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    The chemical composition, antioxidant and antibacterial activities of essential oils isolated by hydrodistillation from the aerial parts of Tunisian Thymus capitatus Hoff. et Link. during the different phases of the plant development, and from different locations, were evaluated. The chemical composition was analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The main components of the essential oils were carvacrol (62–83%), p-cymene (5–17%), γ-terpinene (2–14%) and β-caryophyllene (1–4%). The antioxidant activity of the oils (100–1000 mg l−1) was assessed by measurement of metal chelating activity, the reductive potential, the free radical scavenging (DPPH) and by the TBARS assay. The antioxidant activity was compared with that of synthetic antioxidants: butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). Both the essential oils and BHA and BHT showed no metal chelating activity. Although with the other methodologies, there was a general increase in the antioxidant activity, with increasing oil concentration, maxima being obtained in the range of 500 and 1000 mg l−1 for flowering and post-flowering phase oils. Major differences were obtained according to the methodology of antioxidant capacity evaluation. Antibacterial ability of Th. capitatus essential oils was tested by disc agar diffusion against Bacillus cereus, Salmonella sp., Listeria innocua, four different strains of Staphylococus aureus (C15, ATCC25923, CFSA-2) and a multi-resistant form of S. aureus (MRSA-2). Antibacterial properties were compared to synthetic antibiotics. Higher antibacterial activity was observed with the flowering and the post-flowering phase essential oils.
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  • The objective of this study was to compare the antimicrobial efficacy of several lavender oils, used singly and in combination, on methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA). Four chemically characterized essential oils from Lavandula angustifolia, L. latifolia, L. stoechas, and a necrodane-rich L. luisieri were assessed for their antibacterial activity using the disc diffusion method. All four lavender oils inhibited growth of both MSSA and MRSA by direct contact but not in the vapor phase. Inhibition zones ranged from 8 to 30 mm in diameter at oil doses ranging from 1 to 20 microL, respectively, demonstrating a dose response. At any single dose, the extent of inhibition was very similar irrespective of the chemical composition of the oils or the strain of S. aureus used. Several binary combinations of the oils were tested, and the results showed that the necrodane-rich L. luisieri oil interacted synergistically with L. stoechas (high in 1,8-cineole, fenchone, and camphor) and L. langustifolia (rich in linalool and linalyl acetate) to produce larger inhibition zones than those produced using each oil individually. The results suggest that combinations of lavender oils should be investigated further for possible use in antibacterial products.
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    Due to the emergence of multi-drug resistance, alternatives to conventional antimicrobial therapy are needed. This study aims to investigate the in vitro pharmacological interactions between essential oils (considered valuable as natural therapeutic treatments) and conventional antimicrobials (ciprofloxacin/amphotericin B) when used in combination. Interactions of the essential oils (Melaleuca alternifolia, Thymus vulgaris, Mentha piperita and Rosmarinus officinalis) when combined with ciprofloxacin against Staphylococcus aureus indicate mainly antagonistic profiles. When tested against Klebsiella pneumoniae the isobolograms show antagonistic, synergistic and additive interactions depending on the combined ratio. The R. officinalis/ciprofloxacin combination against K. pneumoniae displayed the most favourable synergistic pattern. The interactions of M. alternifolia (tea tree), T. vulgaris (thyme), M. piperita (peppermint) and R. officinalis (rosemary) essential oils with amphotericin B indicate mainly antagonistic profiles when tested against Candida albicans. While a number of interactions show complete antagonism, others show varied (synergistic, additive and/or antagonistic) interactions, thus the efficacy is dependent on the ratio in which the two components co-exist. The predominant antagonistic interactions noted here, suggests that some natural therapies containing essential oils should be used with caution when combined with antibiotics.