Phytochemical and Biological Investigation of Thymus linearis

Abstract

The crude methanolic extract of Thymus linearis and its fractions were analyzed for their antibacterial and antifungal activities. They exhibited significant antibacterial activity against MDR bacterial strains. The maximum effect was shown by butanolic fraction against S.aureus, K. pneumoniae and Providencia species. The crude methanolic extract and other fractions exhibited low to moderate antibacterial activity. Similarly crude methanolic extract and its various fractions were analyzed for antifungal activity. The crude extract showed good activity against Rhizopus (14mm), Penicillium chrysogenum (10mm) and Aspergillus fumigates (10mm) respectively, while chloroform fraction showed no effect against Rhizopus. The n-hexane fraction showed low to moderate activity against Penicillium chrysogenum. The crude methanolic extract and its various fractions were analyzed for their phytotoxic effect. The phytotoxicity of butanolic fraction was significant, while moderate activity shown by crude methanolic extract, ethyl acetate and chloroform fractions of T. linearis. In in-vitro contact bioassay the n-hexane and butanolic fraction exhibited significant activity resulting 60% mortality of T. casteneum while methanolic fraction exhibited about 40% and 30% mortality of T. casteneum and C.analis respectively. The anthelmintic effect of crude methanolic extract and its solvent fractions showed significant results. The n-hexane and ethyl acetate fraction showed more significant anthelmintic activity, while methanol, chloroform and butanol fractions showed mild to moderate activity against Pheretima posthumas. The crude methanolic extract and its various fractions exhibited a concentration dependent antioxidant effect. The crude extract possessed similar antioxidant effect to that of ascorbic acid, while the antioxidant potential of n-hexane, butanol and chloroform were comparable to that of Butylated hydroxytoluene (BHT). The ethyl acetate fraction showed lowest antioxidant activity. In in-vivo biological activities the crude methanolic extract and its various fractions were being very safe in acute toxicity assay. In analgesic activity the Thymus linearis methanolic extract (TLME) exhibited a dose dependent antinociceptive effect in both peripheral and central analgesic models. Similarly antipyretic effect of TLME was increased as the dose increased from 100 to 300mg/kg. The TLME showed significant antipyretic effect from 2nd hr up to 4th hr of experiment. The TLME, at the dose of 300mg/kg exhibited significant anti-inflammatory response 2hr after the carrageenan injection and sustained throughout the experiment. In nephro and hepato protective activity, the crude methanolic extract and its various fractions showed significant results, and n-butanol, chloroform and crude extract were more nephro and hepato protective while ethyl acetate fraction showed mild nephro and hepato protective activity. The Fourier transform infrared spectroscopy (FTIR) was done of crude methanolic extract and its various solvent fractions which suggested the presence of different new compounds like amides, aldehydes, carboxylic acid, ethers, alcohols and ketones etc, majority of which are not reported formally. Fixed oils were obtained from n-hexane sub-fraction and GC/MS of fixed oils showed presence of important fatty oils which are biologically active. The ethyl acetate and chloroform fraction were subjected to column chromatography (CC) which resulted into the isolation of six pure compounds. The structure elucidation of pure compounds was done using 1H-NMR, 13C-NMR, COSY, NOSY, HMQC, HMBC, UV, IR, EI-MS and HREI-MS. All the compounds were isolated from T. linearis for the first time but they were reported from other sources as well. These compounds were β-Sitosterol, Ursolic acid, 3, 4, 5- Trihydroxybenzoic acid, Oleanolic acid, Benzoic acid and Betulinic acid. The in-vivo and in-vitro biological activities were corresponding with these isolated pure compounds. The antipyretic, antinociceptive and anti-inflammatory activity of β- sitosterol, ursolic acid and oleanolic acid has already been recorded. The antioxidant and antitumor activity of ursolic acid and betulinic acid has also been reported as well. This research activity significantly supported ethnobotanical uses of T. linearis whole plant as a traditional medicine for treatment. In spite of all this further thorough research work on the crude methanolic extract and its various fractions for isolation of secondary metabolites is required. Furthermore research activities on isolated compounds may give directions for potential therapeutic agent for management of different disease.