Aloe vera as a novel solution for overcoming herpes simplex virus drug resistance: an in silico study

Abstract

Herpes simplex virus (HSV) infection has recently become a considerable threat to public health due to its soaring drug resistance trend. Aloe vera, a traditional medicinal plant with a wide range of biological activity, has been suggested as a potential source of antiviral agents. In this study, the potential anti-HSV activities of Aloe vera were examined using the molecular docking approach.
Target proteins associated with HSV were selected, followed by the identification and three-dimensional structure generation of chemical compounds from Aloe vera. The structures were optimized and molecular docking analysis using Auto Dock VINA was employed to assess the affinity of Aloe vera compounds for with crucial for HSV proteins. Additionally, ADMET analysis was conducted to evaluate the pharmacokinetic properties of the identified ligands.
The analysis revealed specific Aloe vera compounds, such as Triterpenoid, Folic acid, Campesterol, Emodin, Isoaloeresin D, and 8-C-Glucosylnaringenin, exhibiting high affinity for various HSV proteins. These compounds demonstrated potential interactions with key viral proteins in host cell infection and replication. Also, pharmacokinetic assessment identified compounds with favorable characteristics. Overall, Campesterol showed the highest affinity in interactions and showed favorable pharmacokinetic features.
The findings suggest that Aloe vera compounds hold promise in addressing HSV infections. It suggests their potential as candidates for further laboratory-based investigations and clinical trials.

Full text

Vol.:(0123456789)
Discover Medicine (2024) 1:28 | https://doi.org/10.1007/s44337-024-00044-4
Discover Medicine
Brief Communication
Aloe vera asanovel solution forovercoming herpes simplex virus drug
resistance: aninsilico study
MohammadHosseinRazizadeh1,2 · SoheilRahmaniFard1 · SaraMinaeian1
Received: 24 May 2024 / Accepted: 12 August 2024
© The Author(s) 2024 OPEN
Abstract
Background Herpes simplex virus (HSV) infection has recently become a considerable threat to public health due to
its soaring drug resistance trend. Aloe vera, a traditional medicinal plant with a wide range of biological activity, has
been suggested as a potential source of antiviral agents. In this study, the potential anti-HSV activities of Aloe vera were
examined using the molecular docking approach.
Materials and methods Target proteins associated with HSV were selected, followed by the identication and three-
dimensional structure generation of chemical compounds from Aloe vera. The structures were optimized and molecular
docking analysis using Auto Dock VINA was employed to assess the anity of Aloe vera compounds for with crucial for
HSV proteins. Additionally, ADMET analysis was conducted to evaluate the pharmacokinetic properties of the identied
ligands.
Results The analysis revealed specic Aloe vera compounds, such as Triterpenoid, Folic acid, Campesterol, Emodin, Isoalo-
eresin D, and 8-C-Glucosylnaringenin, exhibiting high anity for various HSV proteins. These compounds demonstrated
potential interactions with key viral proteins in host cell infection and replication. Also, pharmacokinetic assessment
identied compounds with favorable characteristics. Overall, Campesterol showed the highest anity in interactions
and showed favorable pharmacokinetic features.
Conclusion The ndings suggest that Aloe vera compounds hold promise in addressing HSV infections. It suggests their
potential as candidates for further laboratory-based investigations and clinical trials.
Keywords Herpes simplex virus· Aloe vera· Drug discovery
1 Introduction
Herpes simplex virus (HSV) is a globally distributed human pathogen that causes various diseases such as oral and
genital herpes, as well as more serious infections including encephalitis and neonatal herpes [1, 2]. HSV infection is
of particular importance in the nervous system and can lead to lifelong infections and neurological complications.
There are two subtypes of HSV: HSV1, which is mainly involved in oral infections, and HSV2, which mostly infects
Supplementary Information The online version contains supplementary material available at https:// doi. org/ 10. 1007/ s44337- 024-
00044-4.
* Sara Minaeian, sara.minaeian@gmail.com; Mohammad Hossein Razizadeh, Razizadeh.mh@gmail.com; Soheil Rahmani Fard,
soheilgman@gmail.com | 1Antimicrobial Resistance Research Center, Institute ofImmunology andInfectious Diseases, Iran University
ofMedical Sciences, Tehran, Iran. 2Department ofVirology, School ofMedicine, Iran University ofMedical Sciences, Tehran, Iran.

Vol:.(1234567890)
Brief Communication Discover Medicine (2024) 1:28 | https://doi.org/10.1007/s44337-024-00044-4
genital sites. Currently, 3.7 billion people under 50years old are infected with HSV1 and 417 million people are
infected with HSV2 [3].
Primarily, the virus infects the epithelium by attaching to its receptors nectin-1 and herpesvirus entry mediator
(HVEM) [4]. Subsequently, the virus retrogradely spreads to the peripheral nervous system via direct cell–cell trans-
mission [5]. HSV gradually reaches the peripheral ganglia and even the central nervous system. The infection of the
CNS can lead to herpes simplex encephalitis or milder complications [6]. HSV is the most important cause of sporadic
encephalitis worldwide [7]. Recently, it has been suggested that latent HSV infection is associated with neurodegen-
erative diseases such as Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis by surging the production of
reactive oxygen species (ROS), which leads to mitochondrial dysfunction [8].
Although acyclovir and its related synthetic drugs are currently available to treat HSV infection, their safety and
efficiency have been challenged in recent years due to adverse effects and soaring drug resistance [1, 9–12]. This
highlights the need to develop new anti-HSV drugs that can overcome these obstacles.
Natural products have been investigated and have been involved in the discovery and development of novel anti-
viral options in recent years [9]. Aloe vera is a common plant that has been used for medicinal purposes for centuries
[13]. Aloe vera contains a variety of bioactive compounds such as anthraquinones, polysaccharides, and glycoproteins,
which have anti-inflammatory, immunomodulatory, anti-microbial, and wound-healing properties [14, 15]. Invitro
and clinical studies have shown that Aloe vera possesses anti-HSV effects [16–18]. However, the chemical compounds
that contribute to this property remain to be revealed. The purpose of this study was to investigate the effects of the
chemical compounds of Aloe Vera on main viral proteins involved in HSV replication including HSV glycoprotein B
(gB), glycoprotein D (gD), Infected-cell polypeptide 4 (ICP4), and DNA polymerase using in silico approach.
2 Materials andmethods
2.1 Target selection andoptimization
The three-dimensional structure of HSV-1 gB (PDB: 5v2s), HSV-1 gD (PDB: 3u82), HSV-1 ICP4 (PDB: 5mhk), HSV-1 DNA
Polymerase processivity factor (PDB: 1dml), HSV-1 DNA Polymerase catalytic subunit (PDB: 2gv9), HSV-2 gH and gL
(PDB: 3M1C), and HSV-2 gD (PDB: 4myv) were downloaded from the RCSB protein Data Bank. H2O and non-standard
residues were cleaned from the structure. The protein structure then was subjected to energy minimization by Swiss
PDB viewer (Guex and Peitsch). HSV-1 gH, HSV-1 gL, HSV-2 gB, HSV-2 ICP4, HSV-2 DNA polymerase catalytic subunit,
and HSV-2 DNA polymerase processivity subunit structures were predicted using SWISS-MODEL. The protein predic-
tion details are shown in Table1.
2.2 Ligand selection
The structure of chemical compounds of Aloe vera has been retrieved from PubChem, except those which their three-
dimensional structure was not available. To obtain the three-dimensional structure of ligands, SDF codes were entered
into OPENBABEL and the three-dimensional structures were generated and saved in PDB format and used for docking
analysis. Hydrogen atoms have been added to structures to make structures explicit.
Table 1 Characteristics of the
predicted protein structures
a The SWISS−MODEL template library
Protein GenBank ID SMTL IDaSeq identity GMQE QMEANDisCo global
HSV-1 gH AAG17895.1 3m1c.1.A 80.39% 0.80 0.87 ± 0.05
HSV-1 gL AAA99790.1 3m1c.1.B 76.22% 0.49 0.74 ± 0.07
HSV-2 gB ULT85413.1 5v2s.1.A 90.94% 0.69 0.72 ± 0.05
HSV-2 ICP4 ULT85446.1 5mhk.2.D 96.09% 0.11 0.76 ± 0.05
HSV-2 Pol catalytic subunit ULT85416.1 2gv9.2.A 91.79% 0.75 0.82 ± 0.05
HSV-2 Pol Processivity subunit ULT85428.1 1dml.3.A 84.01% 0.49 0.77 ± 0.05

Vol.:(0123456789)
Discover Medicine (2024) 1:28 | https://doi.org/10.1007/s44337-024-00044-4 Brief Communication
2.3 Molecular docking analysis
In order to perform molecular docking, Auto Dock VINA implemented in PyRx software has been used [19]. To perform
the docking process, the grid box was set around entire protein structures. The docking poses were visually inspected
using BIOVIA Discovery Studio to ensure that they were reasonable and that key interactions (Such as hydrogen bonds
and hydrophobic interactions) were preserved.
2.4 ADMET analysis
The canonical SMILES of the compound were obtained from PubChem and used for physicochemical and pharmacoki-
netics analysis using the Swiss-ADME (SwissADME) web server [20].
3 Results
Chemical compounds of Aloe vera were investigated to nd their ability to form bonds with important HSVs proteins
involved in infecting host cells. Analysis showed that Triterpenoid can attach to gB of both HSVs with the highest anity
(−9.8 for HSV1 gB and −9.2 for HSV2 gB). Also, Triterpenoid showed the highest anity of −8.0 for HSV-1 gD and −8.7
for HSV-2 gD. In the case of HSV gH, Folic acid exhibited the greatest anity (−9.6) for HSV-1 and Campesterol (−9.9)
for HSV-2. For gL, Folic acid (−9.6) for HSV-1 and Triterpenoid (−8.8) for HSV-2 showed higher anities compared with
other compounds.
In the case of ICP4, Emodin (−9.5) for HSV-1 and Folic acid (−9.6) for HSV-2 showed the topmost anities. For the viral
polymerase, Isoaloeresin D (−8.7) and 8-C-Glucosylnaringenin (−8.8) had the highest anities for the catalytic subunit
of HSV-1 and HSV-2, respectively, whereas the anity of binding acyclovir triphosphate was −6.8 and −7.3 for HSV-1
and HSV-2. Also, Triterpenoid showed the highest anity for both HSV-1 (−9.1) and HSV-2 (−8.8) polymerase proces-
sivity unit. Figure1 shows the top ve interactions with the highest anity. The chemical structures of ligands with the
highest anity are depicted in Fig.2. A complete list of ligands and their anity to viral proteins as well as amino acids
involved in the interactions are shown in supplementary tables1 and 2).
Pharmacokinetic assessment of the ligands showed that among the analyzed ligands, Barbaloin, Isobarbaloin, Beta
Sitosterol, Campesterol, Choline, Folic acid, 8-Glucosyl-(S)-aloesol, 8-Glucosyl-7-O-Methylaloediol and 8-C-Glucosylnarin-
genin were not P-glycoprotein substrates, Cytochrome P-450 inhibitors, and showed no blood–brain barrier permeability,
of these, Campesterol, Folic acid, and 8-C-Glucosylnaringenin were among those that interacted with viral proteins with
the highest anity. In the case of other ligands that bound with the highest anity to viral proteins, Triterpenoid and
Isoaloeresin D are P-glycoprotein substrates while they are not cytochrome P-450 inhibitors and do not permeate the
blood–brain barrier (The complete list of SwissADME results is presented in supplementary Table3).
4 Discussion
Both HSV-1 and HSV-2 are responsible for a signicant number of infections worldwide [21, 22]. Perhaps, HSV is the most
prevalent viral cause of neurological diseases [22]. Once HSVs infect the nervous system, they use myriad mechanisms
such as protein aggregation, dysregulation of autophagy, oxidative cell damage, and apoptosis to induce neurodegen-
eration [21]. gB is involved in virus entry and fusion with host cells. It is part of the minimum membrane fusion protein
complex, along with gD and the heterodimer gH/gL, that functions in virus entry and virus-induced cell fusion [23]. ICP4
is a transcription factor that plays a central role in regulating the gene expression that controls HSV infection by regulat-
ing viral transcription and forming a novel DNA recognition complex [24, 25].
While herbal remedies have shown eects in treating various diseases, their mechanism of action remained to be
elucidated [26]. Recent advances and developments in the eld of bioinformatics paved the way for discovering new
therapeutic approaches using plants, especially because of the reduction in number of novel approved drugs and their
tremendous development expenditure [27]. Among over 400 species of the genus Aloe, Aloe Vera the most famous
member which has been studied and showed antimicrobial, anti-inammatory, and anti-tumor activities [28].
Studies have investigated invitro impacts of Aloe Vera on HSV infection. Aloe Vera gel extracts indicated cell compat-
ibility in cytotoxicity assay and also inhibitory eects of various concentrations against HSV-1 [29]. Aloe Vera extracts

Vol:.(1234567890)
Brief Communication Discover Medicine (2024) 1:28 | https://doi.org/10.1007/s44337-024-00044-4
Fig. 1 Five interactions with the highest anity between Aloe vera compounds and HSV proteins: a Campesterol and HSV2 gH; b Triterpe-
noid and HSV1 gB; c Folic acid and HSV1 gH; d Folic acid and HSV1 gL; and e Folic acid and HSV2 ICP4
Fig. 2 Chemical structure of compounds with the highest anity at least for one HSV protein: A Triterpenoid (B) Isoaloeresin D (C) Folic acid
(D) Emodin (E) Campesterol (F) 8-C-Glucosylnaringenin

Vol.:(0123456789)
Discover Medicine (2024) 1:28 | https://doi.org/10.1007/s44337-024-00044-4 Brief Communication
also illustrated antiviral eects against acyclovir-resistant HSV-1 on the HeLa cell line [16]. Another study used the Vero
cell line and achieved similar results on HSV-2 [18]. Besides invitro studies, a clinical trial conducted on patients with
cell culture-conrmed HSV infection exhibited that 0.5% Aloe vera extract in a hydrophilic cream dramatically shortened
the mean time to healing in the experimental group in comparison with the placebo group. Also, 55 of 60 recipients
reported no side-eects while only 5 individuals experienced mil itching which resolved within 24h [17]. Although these
outcomes delineate the antiviral eects of Aloe Vera, the important contributing compounds remain to be illustrated.
According to our results, many Aloe vera compounds could potentially interact with HSV proteins, making this plant an
important candidate for further drug discovery studies with the aim of treating HSV infections. In our study, Triterpenoid,
Folic acid, Campesterol, Emodin, Isoaloeresin D, and 8-C-Glucosylnaringenin showed the highest anities for the viral
proteins, showing their potential ability to be used in further studies. Triterpenoids are plant-derived phytochemicals
and secondary metabolites that can be found in various plants. Triterpenoids have been found to have a wide range of
biological activities, including anti-inammatory, anticancer, and cardioprotective eects [30]. Studies have shown their
antiviral eects against viruses such as Inuenza and Human immunodeciency virus [31, 32]. Folic acid, also known as
folate or vitamin B9, is a water-soluble vitamin that is essential for DNA synthesis and cell growth. Folic acid has been
shown to have antiviral eects on Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) potential by blocking
the viral nucleocapsid protein [33]. Campesterol is a type of phytosterol, which is a plant-derived compound that is struc-
turally similar to cholesterol [34]. An In silico has shown the potential of Campesterol to attach to multiple SARS-CoV-2
proteins [35]. Also, an invitro study revealed its ability to a combination of phytosterols (β-sitosterol, stigmasterol, and
Campesterol) can inhibit Inuenza virus hemagglutinin protein [36]. Noteworthy, our study showed Campesterol as a
potent compound to be used in further studies as it showed high anity and no unfavorable in interaction with gH,
which is necessary for virus infectivity [37]. Emodin is a natural anthraquinone derivative that is found in several plants,
including Aloe vera. invitro studies showed its antiviral eect against hepatitis B virus, possibly through inhibiting viral
polymerase [38]. Moreover, another invitro research on HEp-2 cells showed its property to be used against coxsackievi-
rus B5 and human respiratory syncytial virus [39]. Isoaloeresin D is chromone that was isolated from some Aloe species
including Aloe vera. It is not much known about its potential applications in medicine, especially in the treatment of
viral infections. However, an In silico study showed its potential to bind to SARS-CoV-2 main protease and spike protein
subunit 2 [40]. According to our results, this compound along with 8-C-Glucosylnaringenin showed higher anity than
acyclovir and can be used to inhibit the HSV polymerase protein.
As an in silico study, there are limitations for this research. In silico studies are not solely adequate in pharmacological
assessments before wide usage of drugs. Also, the most eective dosage of the compounds cannot be determined by
in silico analysis. Therefore, while the results provided valuable information about the potential of Aloe vera compounds
to treat HSV infection, we suggest further invitro and invivo studies.
5 Conclusion
HSVs are among the most important viruses responsible for neurological infections. While Acyclovir is mainly used to
treat HSV infection, growing drug resistance poses a signicant threat to the success of the treatment. In this study, we
evaluated chemical compounds of Aloe vera to nd their ability to bond to HSV proteins important for viral entry or
replication using the in silico drug repurposing approach. Results showed that there are various compounds that have
a good potential to attach to those proteins. Accordingly, we suggest conducting invitro research to evaluate their anti-
HSV activity in laboratory and choose the proper compounds to be used in clinical studies.
Author contributions MHR and SM conceptualized the research. MHR and SRF conducted the analysis. All authors participated in draft prepa-
ration and revision.
Funding The article is supported by a grant from Iran University of Medical Sciences (Grant number: 13211).
Data availability All data are available in the supplementary tables.
Declarations
Competing interests The authors declare no competing interests.

Vol:.(1234567890)
Brief Communication Discover Medicine (2024) 1:28 | https://doi.org/10.1007/s44337-024-00044-4
Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which
permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to
the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modied the licensed material. You
do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party
material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If
material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds
the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco
mmons. org/ licen ses/ by- nc- nd/4. 0/.
References
1. Schnitzler P. Essential oils for the treatment of herpes simplex virus infections. Chemotherapy. 2019;64(1):1–7.
2. Samies NL, James SH. Prevention and treatment of neonatal herpes simplex virus infection. Antiviral Res. 2020;176: 104721.
3. Tompa DR, etal. Trends and strategies to combat viral infections: a review on FDA approved antiviral drugs. Int J Biol Macromol.
2021;172:524–41.
4. Vollmer B, Grünewald K. Herpesvirus membrane fusion–a team eort. Curr Opin Struct Biol. 2020;62:112–20.
5. Bello-Morales R, Andreu S, López-Guerrero JA. The role of herpes simplex virus type 1 infection in demyelination of the central nervous
system. Int J Mol Sci. 2020;21(14):5026.
6. Marcocci ME, etal. Herpes simplex virus-1 in the brain: the dark side of a sneaky infection. Trends Microbiol. 2020;28(10):808–20.
7. Abdullahi AM, Sarmast ST, Singh R. Molecular biology and epidemiology of neurotropic viruses. Cureus. 2020;12(8): e9674.
8. Duarte LF, etal. Is there a role for herpes simplex virus type 1 in multiple sclerosis. Microbes Inf. 2022. https:// doi. org/ 10. 1016/j. micinf.
2022. 105084.
9. Treml J, etal. Natural products-derived chemicals: breaking barriers to novel Anti-HSV drug development. Viruses. 2020;12(2):154.
10. Hyun J, etal. Variant Analysis of the thymidine kinase and DNA polymerase genes of herpes simplex virus in Korea: frequency of acyclovir
resistance mutations. Viruses. 2023;15(8):1709.
11. Rousseau A, etal. Acyclovir-resistant herpes simplex virus 1 keratitis: a concerning and emerging clinical challenge. Am J Ophthalmol.
2022;238:110–9.
12. Karrasch M, etal. Rapid acquisition of acyclovir resistance in an immunodecient patient with herpes simplex encephalitis. J Neurol Sci.
2018;384:89–90.
13. Gao Y, etal. Biomedical applications of Aloe vera. Crit Rev Food Sci Nutr. 2019;59(sup1):S244–56.
14. Maan AA, etal. The therapeutic properties and applications of Aloe vera: a review. J Herbal Med. 2018;12:1–10.
15. Singh B, etal. Phytoconstituents and biological consequences of: a focused review Aloe vera. Asian J Pharmacy Pharmacol. 2018;4(1):17–22.
16. Ebrahimi E, etal. Antiviral eects of aloe vera (L.) Burm.f. and Ruta graveolens L extract on acyclovir-resistant herpes simplex virus type
1. J Med plants By-product. 2021;10(1):103–8.
17. Syed T, etal. Management of genital herpes in men with 0.5% Aloe vera extract in a hydrophilic cream: a placebo-controlled double-blind
study. J Dermatol Treatment. 1997;8(2):99–102.
18. Zandi K, etal. Antiviral activity of Aloe vera against herpes simplex virus type 2: an invitro study. Afr J Biotechnol. 2007. https:// doi. org/
10. 5897/ AJB20 07. 000- 2276.
19. Dallakyan S, Olson AJ. Small-molecule library screening by docking with pyrx, in chemical biology: methods and protocols. Springer,
New York: New York, NY; 2015.
20. Daina A, Michielin O, Zoete V. SwissADME: a free web tool to evaluate pharmacokinetics, drug-likeness and medicinal chemistry friendli-
ness of small molecules. Sci Rep. 2017;7(1):42717.
21. Duarte LF, etal. Herpes simplex virus type 1 infection of the central nervous system: insights into proposed interrelationships with neu-
rodegenerative disorders. Front Cell Neurosci. 2019. https:// doi. org/ 10. 3389/ fncel. 2019. 00046.
22. Berger JR, Hou S. Neurological complications of herpes simplex virus type 2 infection. Arch Neurol. 2008;65(5):596–600.
23. Jambunathan N, etal. Two sides to every story: herpes simplex type-1 viral glycoproteins gB, gD, gH/gL, gK, and cellular receptors func-
tion as key players in membrane fusion. Viruses. 2021. https:// doi. org/ 10. 3390/ v1309 1849.
24. Bates PA, DeLuca NA. The polyserine tract of herpes simplex virus ICP4 is required for normal viral gene expression and growth in murine
trigeminal ganglia. J Virol. 1998;72(9):7115–24.
25. Tunnicliffe RB, etal. The herpes viral transcription factor ICP4 forms a novel DNA recognition complex. Nucleic Acids Res.
2017;45(13):8064–78.
26. Kim E, Choi AS, Nam H. Drug repositioning of herbal compounds via a machine-learning approach. BMC Bioinform. 2019;20:33–43.
27. Katiyar C, etal. Drug discovery from plant sources: an integrated approach. Ayu. 2012;33(1):10–9.
28. Rahmani AH, etal. Aloe vera: potential candidate in health management via modulation of biological activities. Pharmacogn Rev.
2015;9(18):120–6.
29. Rezazadeh F, etal. Assessment of anti HSV-1 activity of aloe vera gel extract: an invitro study. J Dent. 2016;17(1):49–54.
30. Ghiulai R, etal. Tetracyclic and pentacyclic triterpenes with high therapeutic eciency in wound healing approaches. Molecules.
2020;25(23):5557.
31. Yu M, etal. Discovery of pentacyclic triterpenoids as potential entry inhibitors of inuenza viruses. J Med Chem. 2014;57(23):10058–71.
32. Wu H-F, etal. Recent advances in natural anti-HIV triterpenoids and analogs. Med Res Rev. 2020;40(6):2339–85.
33. Chen Y-M, etal. Folic acid: a potential inhibitor against SARS-CoV-2 nucleocapsid protein. Pharm Biol. 2022;60(1):862–78.
34. Shahzad N, etal. Phytosterols as a natural anticancer agent: current status and future perspective. Biomed Pharmacother. 2017;88:786–94.

Vol.:(0123456789)
Discover Medicine (2024) 1:28 | https://doi.org/10.1007/s44337-024-00044-4 Brief Communication
35. Dinata R, etal. Repurposing immune boosting and anti-viral ecacy of Parkia bioactive entities as multi-target directed therapeutic
approach for SARS-CoV-2: exploration of lead drugs by drug likeness, molecular docking and molecular dynamics simulation methods.
J Biomol Structure Dynamics. 2023. https:// doi. org/ 10. 1080/ 07391 10221 92797.
36. Ortiz-López T, etal. Bioassay-guided fractionation of erythrostemon yucatanensis (Greenm.) Gagnon & GP lewis components with anti-
hemagglutinin binding activity against inuenza A/H1N1 Virus. Molecules. 2022;27(17):5494.
37. Cairns TM, etal. Epitope mapping of herpes simplex virus type 2 gH/gL denes distinct antigenic sites, including some associated with
biological function. J Virol. 2006;80(6):2596–608.
38. Parvez MK, etal. The anti-hepatitis B virus therapeutic potential of anthraquinones derived from Aloe vera. Phytother Res.
2019;33(11):2960–70.
39. Liu Z, etal. Antiviral eect of emodin from Rheum palmatum against coxsakievirus B5 and human respiratory syncytial virus invitro. J
Huazhong Univ Sci Technol [Med Sci]. 2015;35(6):916–22.
40. Harisna AH, etal. In silico investigation of potential inhibitors to main protease and spike protein of SARS-CoV-2 in propolis. Biochem
Biophys Rep. 2021;26: 100969.
Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional aliations.