OBJECTIVE: This study investigates the effect of methanol extract of M. calabura leaves (MMCL) on hepatic antioxidant and anti-inflammatory activities in CCl4-induced hepatotoxic rat.

MATERIALS AND METHODS: Sprague Dawley rats (n = 6) were treated (p.o.) with 10% DMSO (Groups 1 and 2), 50 mg/kg N-acetylcysteine (Group 3) or, 50, 250, or 500 mg/kg MMCL (Groups 4-6) for 7 consecutive days followed by pretreatment (i.p.) with vehicle (Group 1) or 50% CCl4 in olive oil (v/v) (Groups 2-6) on day 7th. Plasma liver enzymes and hepatic antioxidant enzymes and pro-inflammatory cytokines concentrations were measured while liver histopathology was examined.

AIM OF THE REVIEW: The present review aims to compile an up-to-date review of the progress made in the continuous pharmacological and phytochemistry investigation of K. africana and the corresponding commercial and pharmaceutical application of these findings with the ultimate objective of providing a guide for future research on this plant.

METHOD: The scholarly information needed for this paper were predominantly sourced from the electronic search engines such as Google, Google scholar; publishing sites such as Elsevier, scienceDirect, BMC, PubMed; other scientific database sites for chemicals such as ChemSpider, PubChem, and also from online books.

RESULTS: Pharmacological investigations conducted confirm the anti-inflammatory, analgesic, antioxidant and anticancer activity of the extract of different parts of the plant. Bioactive constituents are found to be present in all parts of the plant. So far, approximately 150 compounds have been characterized from different part of the plant. Iridoids, naphthoquinones, flavonoids, terpenes and phenylethanoglycosides are the major class of compounds isolated. Novel compounds with potent antioxidant, antimicrobial and anticancer effect such as verbascoside, verminoside and pinnatal among others, have been identified. Commercial trade of K. africana has boosted in the las few decades. Its effect in the maintenance of skin has been recognized resulting in a handful of skin formulations in the market.

MATERIALS AND METHODS: Literature abstracts and full text articles from journals, books, reports and electronic searches (Google Scholar, Elsevier, PubMed, Read Cube, Scopus, Springer, and Web of Science), as well as from other relevant websites, are surveyed, analysed and included in this review.

RESULTS: A literature survey of agarwood plant materials showed that they contain sesquiterpenes, 2(-2-phenylethyl)-4H-chromen-4-one derivatives, genkwanins, mangiferins, iriflophenones, cucurbitacins, terpenoids and phenolic acids. The crude extracts and some of the isolated compounds exhibit anti-allergic, anti-inflammatory, anti-diabetic, anti-cancer, anti-oxidant, anti-ischemic, anti-microbial, hepatoprotective, laxative, and mosquitocidal properties and effects on the central nervous system. Agarwood plant materials are considered to be safe based on the doses tested. However, the toxicity and safety of the materials, including the smoke from agarwood incense burning, should be further investigated. Future research should be directed towards the bio-guided isolation of bioactive compounds with proper chemical characterisation and investigations of the underlying mechanisms towards drug discovery.

KEY FINDINGS: T. corymbosa (Roxb. ex Wall.) parts are used as poultice, boiled juice, decoctions and infusions for treatment against ulceration, fracture, post-natal recovery, syphilis, fever, tumours and orchitis in Malaysia, China, Thailand and Bangladesh. Studies recorded alkaloids as the predominant phytochemicals in addition to phenols, saponins and sterols with vast bioactivities such as antimicrobial, analgesic, anthelmintic, vasorelaxation, antiviral and cytotoxicity.