OBJECTIVES: This article compiles the ethnomedicinal uses of CN and its phytochemistry, and thus provides a phytochemical library of CN. It also discusses the known pharmacological and biological effects of CN to enable better investigation of CN.
METHODS: This literature review was limited to articles and websites published in the English language. MEDLINE and Google Scholar databases were searched from December 2014 to September 2016 using the following keywords: "Clinacanthus nutans" and "Belalai gajah". The results were reviewed to identify relevant articles. Information from relevant selected studies was systematically analyzed from contemporary ethnopharmacological sources, evaluated against scientific literature, and extracted into tables.
RESULTS: The literature search yielded 124 articles which were then further scrutinized revealing the promising biological activities of CN, including antimicrobial, antiproliferative, antitumorigenic and anti-inflammatory effects. Few articles discussed the mechanisms for these pharmacological activities. Furthermore, CN was beneficial in small-scale clinical trials for genital Herpes and aphthous stomatitis.
CONCLUSION: Despite the rich ethnomedicinal knowledge behind the traditional uses of CN, the current scientific evidence to support these claims remains scant. More research is still needed to validate these medicinal claims, beginning by increasing the understanding of the biological actions of this plant.
METHODS: The cytotoxic effects of three flavonoids towards rhabdomyosarcoma (RD) cells were first examined using cell proliferation MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay. Compounds found to be non-cytotoxic in RD cells were evaluated for their in vitro antiviral properties against the EV-A71 subgenotype B4 strain 41 (5865/SIN/000009) using antiviral assays. Viral infectivity was determined by reduction of the formation of plaques in RD cells. For the measurement of RNA copy number, the real time quantitative reverse transcription PCR (qRT-PCR) was used. The most potent compound was further evaluated to determine the mode of action of inhibition by time course, virus attachment and entry assays in Vero cells.
RESULTS: Silymarin was shown to exert direct extracellular virucidal effects against EV-A71 at 50% inhibitory concentration (IC50) of 15.2 ± 3.53 μg/mL with SI of 10.53. Similarly, baicalein exhibited direct extracellular virucidal effects against EV-A71 at a higher IC50 value of 30.88 ± 5.50 μg/mL with SI of 13.64. Besides virucidal activity, silymarin was shown to block both viral attachment and entry of EV-A71 to inhibit infection in Vero cells.
CONCLUSIONS: Silymarin has a stronger inhibition activity against EV-A71 in comparison to baicalein. It could serve as a promising antiviral drug to treat EV-A71 infections.
METHODS: Diabetes was induced using streptozotocin (60 mg/kg, i.v.) followed by nicotinamide (210 mg/kg, intraperitoneal (i.p.)). MAD (50 mg/kg) was administered orally for 4 weeks, commencing 15 days after induction of diabetes; resveratrol (10 mg/kg) was used as a positive control. Fasting blood glucose, plasma insulin, HbA1c, liver and lipid parameters were measured, along with antioxidant enzymes and malondialdehyde as an index of lipid peroxidation; histological and immunohistochemical studies were also undertaken.
KEY FINDINGS: MAD normalized the elevated fasting blood glucose levels. This was associated with increased plasma insulin concentrations. MAD alleviated oxidative stress by improving enzymatic antioxidants and reducing lipid peroxidation. Histopathological examination showed significant recovery of islet structural degeneration and an increased area of islets. Immunohistochemical staining showed increased insulin content in islets of MAD-treated rats.
CONCLUSIONS: The results demonstrate an antidiabetic effect of MAD associated with preservation of β-cell structure and function.