No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
In vitro antioxidant, total phenolic content and preliminary toxicity studies of Gmelina philippensis chem
Abstract
Investigation with the crude methanol extract of leaves and flowers of Gmelina philippensis chem. as well as petroleum ether, carbon tetrachloride and dichloromethane soluble partitionates were carried out to evaluate antioxidant activity. It was evaluated by analyzing the bleaching rate of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and phosphomolybdenum total antioxidant assay using, butylated hydroxytoluene (BHT) and ascorbic acid (ASA) as standard antioxidants. The total phenolic content was also determined and expressed in gallic acid equivalent (mg of GAE/g of sample). A great variance was observed for polyphenol content as well as antioxidant activity (1.354 to 10.179 mg GAE/g and DPPH IC 50 9.75 to 35.25 μg/ml) depending on the nature of the solvent used to fractionate the crude extracts. The result demonstrated that carbon tetrachloride soluble fraction of leaves extract revealed the highest amount of phenolic compounds (10.179 mg GAE/g) and also had significant antioxidant activity (IC 50 9.75 μg/ml). A positive correlation was seen between total phenolic content and total antioxidant activity of leaves and flowers of G. philippensis chem. having correlation coefficient (R 2) values of 0.9878 and 0.9385, respectively. The general toxicity of the extractive was studied by brine shrimp lethality bioassay and from the results (LC 50 0.902 to 0.487 μg/ml).
... The Fruits are fleshy, smooth, yellow, and ovoid to obovoid, drupe, and about 2 cm long and appear in June-August. This plant is inherent in the Philippine islands, S.E, Asia and India also distributed in Australia, United States, Malaysia, Vietnam, Thailand, Bangladesh Indonesia and Myanmar [16,17] . Phytochemical screening is critical in discovering novel sources of medicinally and industrially useful chemicals with medicinal relevance to make the best and most sensible use of available natural resources [18][19][20] . ...
... However, the fecal extract was twice as active as the leaf extract. There was a direct correlation between the phenolic content and the antioxidant activity of the fecal and leaf extracts because phenolic compounds contribute directly to antioxidant activity (Re et al., 1999;Chowdhury et al., 2012). The higher total phenolic content observed for the fecal extract can be associated with the release of phenolic compounds linked to the leaf cell walls during the insect's digestive process. ...
Ethnopharmacological relevance
Gmelina philippensis CHAM is an ornamental plant that is distributed in South Asia and warm regions of the Mediterranean area. The plant is traditionally applied in folk medicine for the treatment of diabetes.
Aim of the study
To evaluate the cytotoxic and the antidiabetic activities of the ethanolic extract of G. philippensis aerial parts. To isolate the metabolite(s) responsible for these activities and to elucidate the mechanism of action by molecular docking study.
Materials and methods
Compounds (1–11) were isolated using various chromatographic techniques and their structures were determined by NMR spectroscopic and mass spectrometric analysis. The cytotoxic effect was tested using viability test and MTT assay. Antidiabetic activity was evaluated by measuring the inhibitory activity of the ethanolic extracts and compounds against α-glucosidase and α-amylase activities. Modeling and docking simulations were performed using Molecular Operating Environment software and the crystal structure of protein kinases CDK2, (1PYE) and AKT1 (4GV1), in addition to α-glucosidase (3TOP) and α-amylase (2QV4).
Results
Compounds 2, 3 and 8 were isolated for the first time from the plant and identified as: gmelinol (2), apigenin (3) and tyrosol (8). While β-sitosterol-3-O- β-D-glucopyranoside (4) vicenin-II (7), rhoifolin (9), isorhoifolin (11) were isolated for the first time from the genus, along with and the new iridoid 6-O-α-L-(2″-O-benzoyl-4″-O-trans-p-methoxycinnamoyl)rhamnopyranosyl-1α- β-D-glucopyranoside catalpolgenin (6). In addition, to the previously reported compounds: mixture of β -sitosterol and stigmasterol (1), and 6- O- α-L-(2″,3″,4″-tri-O -benzoyl)rhamnopyranosylcatalpol (5) and 6-O-α-L-(2″-O-trans-p-methoxycinnamoyl)rhamnopyranosylcatalpol (10). The cytotoxic activity against hepatocellular carcinoma (HepG-2) cell lines for compounds 2, 5, 7, 9 and 11 was conducted using cisplatin as a standard. Gmelinol (2) exhibited strong cytotoxic activity against HepG-2 cell lines with IC 50 value of 3.6 ± 0.1 μg/ml which is more potent than the standard cisplatin IC 50 = 8.7 ± 0.9 μg/ml. Molecular modeling of 2 against diverse targets of protein kinases suggested that CDK-2 and AKT-1 could be the dual probable kinase targets for its cytotoxic action. Compound 2 showed α-amylase inhibition activity with IC 50 value of 60.9 (μg/ml) while, compounds 5 showed strong α-glucosidase inhibition activity with IC 50 values of 41.7 (μg/ml) compared to acarbose with IC 50 value of 34.7, 30.6 (μg/ml). Molecular docking of compounds 2 and 5 on α-glucosidase (3TOP) and α-amylase (2QV4) enzymes revealed high binding affinity and active site interactions comparable to native ligand acarbose.
Conclusion
The ethanolic extract of G. philippensis CHAM aerial parts is effective against HepG-2 cell lines, α-amylase and α-glucocidase activities. Biologically guided isolation indicated that compounds 2 and 5 are responsible for these activities. These results were supported by DMF calculations that detected the molecular areas responsible for protein interactions shown via docking studies.
Acacia nilotica, Ocimum sanctum, and Alpinia nigra are used traditionally in different ailments in rural settings of Bangladesh. These medicinal plants were studied for their total phenolic and total flavonoid contents as a partial approach to rationalizing their use. Antioxidant activity was also determined to measure ferric reducing power assay and 1,1 '-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity. A. nilotica showed the highest total phenolic content while O. sanctum showed the highest flavonoid contents among the studied three plants. Similarly, IC50 values of the extracts of A. nilotica, O. sanctum and A. nigra against DPPH were 39.62, 48.81, 70.85 µg/ml, respectively. The reducing power of the extract was found to be concentration dependent and O. sanctum showed the highest reducing power followed by A. nilotica. The reducing power of these two plants was fairly close to the positive control of ascorbic acid. Further studies are suggested such as in-vivo testing and elucidation of the mechanism of action of inherited bioactive compounds to support its folkloric use in the treatment of diseases.
Phytogeographically, southern Thailand is covered by tropical rain forest which high plant diversity is existing. Nevertheless, scanty study of medicinal plant diversity has been performed. This study aimed to survey medicinal plants from tropical rain forest of Hua Khao Subdistrict, Singha Nakhon District, Songkhla Province. It was carried out during July 2012-December 2012. Semi-structure interviews were performed to 5 key informants. The main criteria for consulting were plant vernacular name, plant part used, preparation, route of administration and properties. Plant identification and voucher specimens were done. The data were analyzed by descriptive statistics and interpretation. Totally, eighty-two species belonging to 69 genera and 48 families were recorded. Rubiaceae was the family with most species used (6 species). The most frequently utilized plant part was underground part (32.73%). Medicinal plants found could be categorized into 31 groups according to their properties, among them antipyretic drugs were mostly found with species utilized (20.80%). Decoction and oral were mostly used as drug preparation method and administration route, respectively. Local properties of 19 medicinal plants were consistent to their report on pharmacological activities. This study is useful for compilation of local knowledge on medicinal plant use for further planning in drug development, sustainable use or conservation of medicinal plants.
A spectrophotometric method has been developed for the quantitative determination of antioxidant capacity. The assay is based on the reduction of Mo(VI) to Mo(V) by the sample analyte and the subsequent formation of a green phosphate/Mo(V) complex at acidic pH. The method has been optimized and characterized with respect to linearity interval, repetitivity and reproducibility, and molar absorption coefficients for the quantitation of several antioxidants, including vitamin E. The phosphomolybdenum method, in combination with hexane monophasic extraction, has also been adapted for the specific determination of vitamin E in seeds. The results obtained with the proposed method were validated by comparison with a standard HPLC method. The phosphomolybdenum method is routinely applied in our laboratory to evaluate the total antioxidant capacity of plant extracts and to determine vitamin E in a variety of grains and seeds, including corn and soybean.
Phenolics are a widely recognized, fundamental quality component of grapes and wines. They are responsible for key wine properties, including color, bitterness, astringency, and longevity. Although many methods are available for measuring grape and wine phenolics, few are suited for rapid, routine analyses in a winery laboratory setting. All current published methods that are within the economic realm of routine winery use require a spectrophotometer. This review concentrates on the spectrophotometric methods designed to measure different phenolic components in grapes and wines, including tri-stimulus, total phenolics, protein precipitable tannins, and color components.
Ulosantoin (2), a phosphorylated hydantoin, has been isolated from organic soluble extracts of the sponge Ulosa ruetzleri and found to exhibit marked insecticidal activity against tobacco hornworm larvae and cockroaches. The structure was determined by X-ray diffraction analysis. A structurally related compound, dimethyl N2-creatininylphosphate (1), was also isolated from the sponge extracts, but was inactive in the insecticidal screens.
The antiradical activities of various antioxidants were determined using the free radical, 2,2-Diphenyl-1-picrylhydrazyl (DPPH*). In its radical form. DPPH* has an absorption band at 515 nm which dissappears upon reduction by an antiradical compound. Twenty compounds were reacted with the DPPH* and shown to follow one of three possible reaction kinetic types. Ascorbic acid, isoascorbic acid and isoeugenol reacted quickly with the DPPH* reaching a steady state immediately. Rosmarinic acid and δ-tocopherol reacted a little slower and reached a steady state within 30 min. The remaining compounds reacted more progressively with the DPPH* reaching a steady state from 1 to 6 h. Caffeic acid, gentisic acid and gallic acid showed the highest antiradical activities with a stoichiometry of 4 to 6 reduced DPPH* molecules per molecule of antioxidant. Vanillin, phenol, γ-resorcylic acid and vanillic acid were found to be poor antiradical compounds. The stoichiometry for the other 13 phenolic compounds varied from one to three reduced DPPH* molecules per molecule of antioxidant. Possible mechanisms are proposed to explain the experimental results.
Six new iridoids, 6-O-alpha-L-(2"-O-, 3"-O-, 4"-O-tribenzoyl)rhamnopyranosylcatalpol, 6-O-alpha-L-(2"-O-, 3"-O-dibenzoyl, 4"-O-cis-p-coumaroyl)rhamnopyranosylcatalpol, 6-O-alpha-L-(2"-O-, 3"-O-dibenzoyl, 4"-O-trans-p-coumaroyl)rhamnopyranosylcatalpol, 6-O-alpha-L-(2"-O-benzoyl, 3"-O-trans-p-coumaroyl)rhamnopyranosylcatalpol, 6-O-alpha-L-(2"-O-, 3"-O-dibenzoyl)rhamnopyranosylcatalpol, and gmephiloside as well as five known monoacyl and diacyl rhamnopyranosylcatalpol derivatives were isolated from the aerial parts of Gmelina philippensis. Their structures were established by spectroscopic means. Additionally, the known iridoids catalpol, geniposidic acid, gardoside, and 8-epi-loganic acid were identified and quantified by GC and GC-MS. The taxonomic significance of rhamnopyranosylcatalpol derivatives and iridoid acids as chemical characters is discussed.
Gmelina philippensis Cham Plant Resources of South Iridoid glycosides from Gmelina philippensis
- J L C H Chung Rck Van Valkenburg
- N Bunyapraphatsara
Chung RCK (2001). Gmelina philippensis Cham.In: van Valkenburg, J.L.C.H. and Bunyapraphatsara, N. (Editors). Plant Resources of South-East Asia No. 12(2): Medicinal and poisonous plants 2. Backhuys Publisher, Leiden, The Netherlands, p. 281. Helfrich E, Rimpler H (2000). Iridoid glycosides from Gmelina philippensis. Phytochemistry, 54(2): 191-199.
Gmelina philippensis Cham Plant Resources of South
- Rck Chung
- J L C H Van Valkenburg
- N Bunyapraphatsara
Chung RCK (2001). Gmelina philippensis Cham.In: van Valkenburg,
J.L.C.H. and Bunyapraphatsara, N. (Editors). Plant Resources of
South-East Asia No. 12(2): Medicinal and poisonous plants 2.
Backhuys Publisher, Leiden, The Netherlands, p. 281.