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Ethnopharmacological relevance Momordica charantia Linnaeus (Cucurbitaceae) has been extensively used traditionally as food and herbal medicine for type 2 diabetes mellitus in Asia, Brazil, and east Africa. In vitro and in vivo studies suggest its glycemic control potential; however, clinical studies produced conflicting results. Aim of the study To evaluate the efficacy of M. charantia preparations in lowering elevated plasma glucose level in prediabetes and type 2 diabetes mellitus patients. Methods Electronic search of the Cochrane library, PubMed®, CINAHL, and SCOPUS databases was done from 1st January 1960–30th April 2018 without language restriction. Two independent reviewers extracted data and assessed risk of bias of articles. Revman var. 5.3 software was used for data synthesis in meta-analysis. Heterogeneity was assessed using Chi-square and I2 tests. Treatment effect was estimated using mean difference at follow up in outcome measures between M. charantia preparations and placebo or oral hypoglycemic agents control group. The protocol of this study has a registration number PROSPERO CRD42018083653. Results Ten studies of type 2 diabetes mellitus (n = 1045) were included in the meta-analysis. They had 4–16 weeks follow up and overall moderate to high risk of bias. Compared to placebo, M. charantia monoherbal formulation significantly reduces FPG, PPG and HBA1c with mean difference of − 0.72 mmol/L, (95% CI: −1.33, −0.12), I2 = 14%, − 1.43 mmol/L, (95% CI: −2.18, −0.67), I2 = 0, − 0.26%, (95% CI: -0.49, −0.03), I2 = 0 respectively. M. charantia also lowered FPG in prediabetes (mean difference −0.31 mmol/L, n = 52); the evidence was downgraded to low quality because the study had unclear risk of bias and inadequate sample size. No serious adverse effects were reported. Conclusion M. charantia adjunct preparations improved glycemic control in T2DM patients. However, this conclusion is based on low to very low quality evidences for the primary outcomes and sparse data for several safety outcomes, thus, warrant further research. Particularly needed are the researches that focus on standardizing M. charantia formulation and determine its efficacy and safety in clinical trials with adequate sample size, designed with random sequence generation, allocation concealment of intervention and blinding of both research personnel and participants.

Hepatitis C Virus (HCV) infection represents a huge burden on healthcare systems worldwide. Vachellia nilotica (V. nilotica) is a widely used plant specie in folk medicine for viral diseases and in some communities for HCV infection. However, little is known regarding its role and possible mechanisms in the prevention and treatment of this viral infection. This review presents ethno-pharmacological, in vitro and in vivo shreds of evidence of the role and underlying mode of action of V. nilotica and its implication in treatment and complication management of HCV infection. PubMed, Library of Congress, SCOPUS, Science Direct and Google scholar databases were searched. Twenty-eight articles of which 15 were in vitro while remaining were in vivo studies were reviewed. V. nilotica's modes of antiviral activity are direct inactivation of HCV and inhibition of HCV NS3 protease. Its immuno-modulatory activity showed by immune cell proliferation and inhibition of immunosuppressive cytokine. V. nilotica's anticancer activity through inhibition of oxidative stress, inhibition of chromosomal aberrations and enhancement of antioxidant enzymes could be beneficial in treating HCV infection and delaying its progression to cancer. It can be inferred that V. nilotica could be a promising source of anti-hepatitis C virus drug leads with the ability to prevent its long-term sequelae while promoting immune competence. Further studies are needed to explore the applicability of the herb to clinical settings.

Regimens of current drugs for tuberculosis are lengthy and are associated with many adverse effects. Currently, the emergence of different resistant strains has been observed. This urges a need for the discovery and development of novel drugs. The main sources of drug lead candidates are based on natural products. Zanthoxylum leprieurii, Lantana camara, and Cryptolepis Sanguinolenta are among the plants that have antimycobacterial activity. Recent technological methods, such as metabolomics, can rapidly detect and identify active compounds from medicinal plants. In this review, we aim to provide an overview and discussion of the antimycobacterial activity, phytochemical analysis and toxicity profile of these plants and their products as well as the potential of metabolomic fingerprinting of medicinal plants with a given activity on microbes, in the search for the potential drug hit molecules. The information for this review was extracted from databases such as Excerpta Medica Database, Google Scholar, Springer, and PubMed Central. Primary studies, using a combination of the keywords antimycobacterial medicinal plant, multidrug-resistant tuberculosis, phytochemistry, toxicity, Zanthoxylum leprieurii, Lantana camara, Cryptolepis sanguinolenta, and plant metabolomics/metabolic fingerprinting of plant extracts, have been considered. The above-mentioned plant species showed antimycobacterial activity against drug-resistant strains of M. tuberculosis. They may provide potential candidates for novel drugs against multidrug-resistant tuberculosis. However, extensive work is still needed. To our knowledge, there is no or limited literature that reports the metabolic fingerprints of these plants. The analysis of the metabolite fingerprints of medicinal plants with similar antimicrobial activity could be important to determine whether the activity results from common metabolites within different plant species. This review shows that these plants are potential candidates to provide drug hits against multidrug-resistant tuberculosis strains. Future studies of compound optimization, in vivo safety and efficacy, as well as of the specific mechanisms of action are however required.