Endemic and Indigenous Plants from Mascarene Islands with Antiviral Propensities.

BACKGROUND: Antiviral resistance and inefficiency of available antiviral drugs to effectively treat viral infections have prompted many researchers worldwide to explore medicinal plants and their isolated compounds as alternative antivirals. The rich flora from the Mascarene Islands has also been thoroughly studied for their wide therapeutic activities, including their antiviral properties. OBJECTIVE: The aim of this review is to highlight the antiviral propensities of Mascarene endemic and indigenous medicinal plants. METHODOLOGY: A review of the literature was conducted via major databases and other primary sources of information. The inhibitory concentration/effective dose causing 50% viral inhibition (IC50/ED50), cytotoxic concentration causing 50% reduction in cell viability (CC50), and selectivity index (SI) were reported, and mechanisms of antiviral action were also discussed. RESULTS: Stillingia lineata was the most effective against chikungunya virus (SI: 10.9), and among its isolated compounds, 12-O-acetylphorbol-13(2″-methyl)- butyrate and 12-deoxyphorbol- 13(2″-methyl)butyrate were the most potent and selective inhibitors of chikungunya virus replication (SI: 41 and >240, respectively). 12-O-acetylphorbol-13(2″-methyl)- butyrate, 12ß-O-[nona- 2Z,4E,6E-trienoyl]-4α-deoxyphorbol-13-butyrate, 12-deoxyphorbol-13(2″-methyl)butyrate, and 12-deoxyphorbol-13-[8'-oxohexadeca-2E,4E,6E-trienoate showed strong selective antiviral effect on human immunodeficiency virus-I (SI: 36-899) and II (SI: 33-2056). Obetia ficifolia and Erythroxylon laurifolium were most active against the herpes virus (SI: 18.5 and 16, respectively). Labourdonnaisia glauca showed potent anti-poliovirus activity (SI: 40), while Badula insularis, Labourdonnaisia glauca and Myonima violacea were active against rhinovirus (SI: 1.3-2.5). Both anti-zika and anti-dengue virus activities were reported for Aphloia theiformis, Doratoxylon apetalum, Phyllanthus phillyreifolius and Psiloxylon mauritianum. CONCLUSION: Promising spectrum of antiviral properties notably against zika, dengue, chikungunya, polio-, rhino-, herpes, and human immunodeficiency viruses were presented by the Mascarene plants suggesting them as viable candidates for the potential development of effective natural antiviral drugs.

GC/MS Profiling, In Vitro and In Silico Pharmacological Screening and Principal Component Analysis of Essential Oils from Three Exotic and Two Endemic Plants from Mauritius.

The chemical and pharmacological profiles of essential oils (EOs) hydrodistilled in yields of 0.03-0.77 % (w/w) from three exotic (Cinnamomum camphora, Petroselinum crispum, and Syzygium samarangense) and two endemic (Pittosporum senacia subsp. senacia and Syzygium coriaceum) medicinal plants were studied. GC-MS/GC-FID analysis of the EOs identified the most dominant components to be myristicin (40.3 %), myrcene (62.2 %), 1,8-cineole (54.0 %), ß-pinene (21.3 %) and (E)-ß-ocimene (24.4 %) in P. crispum, P. senacia and C. camphora, S. samarangense and S. coriaceum EOs, respectively. All EOs were found to possess anti-amylase (0.70-1.50 mM ACAE/g EO) and anti-tyrosinase (109.35-158.23 mg KAE/g) properties, whereas no glucosidase inhibition was displayed. Only Syzygium EOs acted as dual inhibitors of both acetyl- and butyryl-cholinesterases, while P. senacia and C. camphora EOs inhibited acetylcholinesterase selectively and P. crispum EO was inactive (AChE: 4.64-4.96 mg GALAE/g; BChE: 5.96 and 7.10 mg GALAE/g). Molecular docking revealed 1,8-cineole to present the best binding affinities with butyrylcholinesterase, amylase and tyrosinase, while both myristicin and ß-pinene with acetylcholinesterase and finally ß-pinene with glucosidase. In vitro antioxidant potency was also demonstrated in different assays (DPPH: 13.52-53.91 mg TE/g, ABTS: 5.49-75.62 mg TE/g; CUPRAC: 45.38-243.21 mg TE/g, FRAP: 42.49-110.64 mg TE/g; and phosphomolybdenum assay: 82.61-160.93 mM TE/g). Principal component analysis revealed the EOs to differ greatly in their bioactivities due to their chemodiversity. This study has unveiled some interesting preliminary pharmacological profiles of the EOs that could be explored for their potential applications as phytotherapeutics.