Plectranthus barbatus: A Review of Phytochemistry, Ethnobotanical Uses and Pharmacology – Part 2

Abstract

Pharmacology ! Plectranthus barbatusStudies on several extracts with various polarities obtained from different parts of P. barbatus revealed a number of pharmacological properties that may justify most of the traditional uses of P. barbatus, for example, organic extracts were reported to possess anti-inflammatory, antimicrobial [1, 2], antioxidant [3], cytotoxic [4], hypotensive [5,6], spasmolytic [7], hepatoprotective [8] and antifeedant [9] activities as well as activity against Ehrlichʼs ascites tumor in mice [10]. An alcoholic extract of the P. barbatus roots was shown to exhibit marked inhibitory action against Escherichia coli toxin-induced secretory response in rabbits and guinea pig ileal loops [11]. It has been shown that a hydroalcoholic extract of P. barbatus (880 mg/kg/day) exerted a variety of toxic effects on the different periods of pregnancy in rats; for example, in the period before embryo implantation, it caused a delay in fetal development and anti-implantation and, after embryo implantation, a delay in the development associated with maternal toxicity [12]. The water extract of P. barbatus leaves was found to exert hypoglycemic, hypotensive and antispasmodic activities [13]. It has been demonstrated that the water extract (WE) of the stems and leaves, at a dose of 1 g/kg p. o., shortened the sleeping time induced by pentobarbital by 37 %, and at a dose of 2 g/kg p. o. enhanced the intestinal transit of charcoal by 30% in mice. The WE (2 g/kg/intraduodenal) also reduced the gastric secretions (3.9 ± 1.0 to 0.5 ± 0.2 mL/4 h), and total acid secretion (34.4 ± 11.0 to 2.7 ± 0.5 mEq/L) and raised gastric pH (2.2 ± 0.3 to 6.5 ± 0.8) in rats. The treatment with WE (2 g/ kg p. o.) was also found to protect against lesions induced by ethanol or cold-restraint stress, in pylorus-ligated rats [14]. Similar results were obtained by Schultz et al. [15] who reported that the WE of the leaves (0.5-0.1 g/kg) injected into the duodenal lumen decreased the volume (62 and 76 %) and total acidity (23 and 50%) of gastric Abstract ! Plectranthus barbatus Andr. is one of the most important species of the genus Plectranthus L′ Herit. (Lamiaceae), with a wide variety of traditional medicinal uses in Hindu and Ayurvedic traditional medicine as well as in the folk medicine of Brazil, tropical Africa and China. The plant has therefore been an attractive target for intensive chemical and pharmacological studies up to now. This review presents data about the phytochemistry, ethnobotanical uses and pharmacology of Plectranthus barbatus as well as the pharmacology of its constituents. In addition to essential oil, abietane diterpenoids and 8,13-epoxy-labd-14-en-11-one diterpenoids are the main constituents found in Plectranthus barbatus. The major ethnobotanical uses are for intestinal disturbance and liver fatigue, respiratory disorders, heart diseases and certain nervous system disorders. Forskolin as one of the major constituents with its unique adenylyl cyclase activation that underlies the wide range of pharmacologic...

Gene Discovery of Modular Diterpene Metabolism in Nonmodel Systems

“…Diterpene pharmaceuticals include the anticancer drugs taxol derived from Taxus species (Jennewein and Croteau, 2001) and ingenol-3-angelate from Euphorbia peplus (Li et al, 2010), the cAMP-regulating and vasodilator drug forskolin from Coleus forskohlii (Alasbahi and Melzig, 2010b), and the analgesic and antidiabetic drug candidate marrubiin from species of Marrubium (Mnonopi et al, 2012). Beyond pharmaceuticals, examples of industrially used plant diterpenes are steviol glycosides sold as natural sweeteners (Goyal et al, 2010), sclareol produced in Salvia sclarea (Caniard et al, 2012) as a source of ambroxide fragrances, and diterpene resin acids used as a large feedstock for industrial resins, inks, and coatings ).…”

Manoyl Oxide (13R), the Biosynthetic Precursor of Forskolin, Is Synthesized in Specialized Root Cork Cells in Coleus forskohlii

“…The diverse known and potential pharmaceutical applications of forskolin extend from alleviation of glaucoma (Wagh et al, 2012) and anti-HIV or antitumor activities (Li and Wang, 2006) to treatment of hypertension and heart failure (Yoneyama et al, 2002). The efficacy of forskolin relies on activation of the adenylate cyclase enzyme (Seamon et al, 1981;Daly, 1984), leading to a marked increase of the intracellular level of cAMP in mammalian in vitro and in vivo systems (Alasbahi and Melzig, 2010b). The semisynthetic forskolin derivative NKH477 has been approved for commercial use in Japan for treatment of cardiac surgery complications, heart failure, and cerebral vasospasm (Toya et al, 1998;Kikura et al, 2004), while a forskolin eye drop solution was recently approved as an effective treatment for glaucoma (Wagh et al, 2012).…”

Phytochemical investigation GC-MS analysis and <i>in vitro</i> antimicrobial activity of <i>Coleus forskohlii</i>

“…It possesses antianaphylactic, antiobesity, amebicidal, gastroprotective, bronchodilating, antiaging, antioxidant, anti-inflammatory, and anticancer activities. It is being used exclusively for weight management and hypotension (Alasbahi and Melzig, 2010;Murugesan et al, 2012;Shivaprasad et al, 2014). In this study, the antimicrobial efficacy of various organic extracts of C. forskohlii was studied and phytochemical constituent present in extracts were identified by GC-MS method.…”