Chemical Characterisation and a Comparative Study on Multi-Target Biological Activities of Root Part Extracts of Coleus barbatus (Andrews) Bent. ex G. Don with its Isolated Compound, Forskolin

Objective The present study was aimed on the comparative investigation of chemical composition and biological activities of Coleus barbatus root part ethyl acetate extract (CBREE) with its non-polar fraction, polar fraction and isolated compound, forskolin. Methodology The analysis of extracts was carried out by gas chromatography-mass spectrometry (GC-MS). Along with the biochemical assay, the biological activities were investigated in terms of antioxidant, in vitro anti-inflammatory, herbicidal, antibacterial, antifungal and anti-feedant properties. Results GC-MS analysis led to the identification of 73 compounds contributing 83.3% in CBREE, while 74 and 57 components contributing 87.2% and 78.7% were identified in non-polar and polar fraction of ethyl acetate extract respectively. CBREE was dominated by bornyl acetate (6.5%), decanal (6.5%), n-hexatriacontane (6.4%) and forskolin (4.6%), while the non-polar fraction was dominated by 1-(1-heptadecynyl) cyclopentanol (7.7%), bornyl acetate (6.7%) and decanal (5.5%) and the polar fraction was dominated by forskolin (36.0%) and spiro[4.5]decan-7-one, 1,8-dimethyl-8,9-epoxy-4-isopropyl (6.1%). The extracts exhibited good to moderate biochemical assay quantified in terms of total phenolic, total flavonoid and total orthodihydric phenol content. The extracts and isolated compound forskolin showed significant antioxidant potential. Forskolin showed good anti-inflammatory activity (89.40%) compared to CBREE (86.37%), polar fraction (82.78%) and non-polar fraction (79.92%) of ethyl acetate extract. Forskolin showed good herbicidal potential in term of root and shoot growth inhibition than the extracts against Raphanus raphanistrum subsp. sativus seeds. Forskolin exhibited more antibacterial potential against Bacillus cereus and Escherichia coli than the extracts. The extracts and isolated compound forskolin exhibited good to moderate antifungal activity against Alternaria alternata and Curvularia lunata .Isolated compound forskolin exhibited a strong anti-feedant activity than extracts against third instar larvae of Spilosoma obliqua . Conclusions The isolated compound forskolin has much more potential than the extracts to act as an anti-inflammatory, herbicidal, antibacterial and anti-feedant agent. Based on these observation it can be inferred that for the development of environmentally benign drugs and pesticides the herb Coleus barbatus can be used as natural source due to its abundant growth and world over distribution.