Protective effect of Lannea coromandelica Houtt. Merrill. against three common pathogens

Ethnomedicinal, Chemical, and Biological Aspects of Lannea Species-A Review

Lannea L. genus belongs to the Anacardiaceae botanical family and has long been used in traditional medicinal systems of many countries to manage several health conditions, but no studies have been conducted regarding its usefulness as a source of herbal medicine for human use. A literature review was conducted on scientific papers indexed on B-On, Pubmed, and Web of Science databases. Our results showed that medicinal plants from this botanical genus, mostly constituted by bark and leaf, are often used to approach a wide variety of disease symptoms, like fever, inflammatory states, pain, and gastrointestinal disorders. Phytochemical profiles of Lannea species revealed that phenolic acid derivatives including hydroquinones, phenolic acids, flavonoids, condensed tannins, and triterpenoids are the main classes of secondary metabolites present. Among the total of 165 identified compounds, 57 (34.5%) are flavonoids, mostly quercetin- and myricetin-derived flavonols and catechin and epicatechin flavan-3-ol derivatives also containing a galloyl group. In vitro and in vivo studies allowed the identification of 12 different biological activities, amongst which antimicrobial, antioxidant, anti-inflammatory, and cytotoxic activities were the most frequently cited and observed in in vitro essays. Our review contributes useful information for the scientifical validation of the use of Lannea species in traditional medicinal systems and shows that more research needs to be conducted to better understand the concrete utility of these as herbal medicines.

Lannea coromandelica (Houtt.) Merr. Induces Heme Oxygenase 1 (HO-1) Expression and Reduces Oxidative Stress via the p38/c-Jun N-Terminal Kinase-Nuclear Factor Erythroid 2-Related Factor 2 (p38/JNK-NRF2)-Mediated Antioxidant Pathway

The leaves of Lannea coromandelica (Houtt.) Merr. are used in the Garo, Pahan, and Teli tribal communities of Bangladesh as a traditional medicinal plant to treat hepatitis, diabetes, ulcers, heart disease, and dysentery. However, there have been limited phytochemical and biological studies on the bark of L. coromandelica. This study aimed to investigate the antioxidant activities of L. coromandelica bark extract (LCBE) and the underlying mechanism using RAW 264.7 cells. The LCBE was analysed by high-pressure liquid chromatography (HPLC) to detect its key polyphenolic compounds. Various in vitro antioxidant assays were performed using RAW 264.7 cells to assess the antioxidant effects of the LCBE and to understand the underlying molecular mechanism. HPLC revealed the presence of gallic acid, (−)-epigallocatechin-3-gallate, catechin, chlorogenic acid, and caffeic acid in the LCBE. The extract showed a very potent capacity to scavenge numerous free radicals through hydrogen atom transfer and/or electron donation and also quenched cellular reactive oxygen species (ROS) generation without showing any toxicity. The LCBE was found to combat the oxidative stress by enhancing the expression, at both transcriptional and translational levels, of primary antioxidant enzymes as well as phase II detoxifying enzymes, especially heme oxygenase 1, through the upregulation of the nuclear factor erythroid 2-related factor 2 (NRF2)-mediated pathway in RAW 264.7 cells via the phosphorylation of p38 kinase and c-Jun N-terminal kinase (JNK). The LCBE exhibited strong antioxidant activities and mitigated the cellular ROS production. These results provide scientific evidence of its potential as an ideal applicant for a cost-effective, readily available, and natural phytochemical, as well as a strategy for preventing diseases associated with oxidative stress and attenuating disease progress.

Ethnomedicinal plants used to treat skin diseases by Tharu community of district Udham Singh Nagar, Uttarakhand, India

ETHNOPHARMACOLOGICAL RELEVANCE

Tharu community is the largest primitive indigenous community of the Uttarakhand, India. In this article we have scientifically enumerated medicinal plants and herbal preparations used by the Tharu community to treat various skin diseases, and discussed dermatological properties of these plants in the light of previous ethnomedicinal, microbiological, pharmacological, toxicological, phytochemical and clinical studies.

MATERIALS AND METHODS

Ethnomedicinal survey was conducted in different villages of Tharu community located in district Udham Singh Nagar, Uttarakhand, India. Ethnomedicinal information on plants used to treat various skin diseases was collected from 122 individuals (93 males and 29 females), including 35 experienced herbal practitioners and 87 local villagers. For each of the recorded plant species the use value (UV) and fidelity level (FL) was calculated. The informant consensus factor (Fic) was also calculated to find out the homogeneity in the information given by the informants.

RESULTS

A total of 90 plant species belonging to 86 genera and 48 families were used by the Tharu community to treat various skin diseases viz., wounds (38 spp.), boils (32 spp.), cuts (18 spp.), leprosy (11 spp.), eczema (10 spp.), itching (7 spp.), ringworm (5 spp.), burns (4 spp.), leucoderma (4 spp.), cracked heels (2 spp.), dandruff (3 spp.), body infection (2 spp.), chilblains (2 spp.), hair fall (2 spp.) and toes infection (2 spp.). Information on botanical name, family, vernacular name, ailments treated, mode and dose of herbal preparations, UV and FL values are provided for each of the recorded species. According to UV value most preferred plant species used to treat skin diseases by Tharu community was Ricinus communis L. followed by Tridax procumbens (L.) L., Azadirachta indica A. Juss., Ageratum conyzoides and Allium cepa L.

CONCLUSIONS

The present study has revealed significant information on various medicinal plants used to treat skin diseases by Tharu community. Literature review has confirmed most of the claims made by the Tharu community regarding treatment of various skin diseases by the reported plants. The literature review has also revealed that products from very few of the reported plants are available in market, while most of the reported plants are still under preclinical or clinical trials. There are various known phytochemicals, and antibiotic, antibacterial, antiviral and antifungal agents present in these plants which may be synthesized or transformed to make pharmaceuticals. Some of the reported plants have shown promising results in preclinical trails and there is a need of clinical trials to see their safety and efficacy in treating various skin diseases. These plants may be targeted for development of new medicines, ointments or drugs for the treatment of skin diseases. However further toxicological, preclinical and clinical studies are needed to validate claims about little worked out plant species reported in the present study viz., Sida cordata (Burm. F.) Borss. Waalk., Millettia extensa (Benth.) Baker, Caesulia axillaris Roxb., Ehretia laevis Roxb., Vanda tessellate (Roxb.) Hook. Ex G.Don. and Eualaliopsis binata (Retz.) C.E. Hubb. Further studies on these plants are recommended to assess their potential in development of new skin care products.