Monthly variation in biomass yield phytochemicals and antimicrobial activity of Mentha longifolia L and Mentha piperita L in Lower Himalaya

Abstract

newline xiv newlineABSTRACT newlineMedicinal plants in Himalaya region is the source of valuable drugs and medicines. Mentha is newlineone of the most important genus of family Lamiaceae which is known for its medicinal and newlinearoma-therapeutic properties since the ancient times. Mentha longifolia and Mentha piperita newlineare the two important medicinal plants present in the Indian Himalayan region. The extracted newlineoil and purified extracts from these two plants are utilised as a traditional remedy to treat newlineanorexia, nausea, bronchitis, flatulence, liver complaints and ulcerative colitis. The present newlinestudy deals with to investigate monthly variation in biomass yield, phytochemicals and newlineantimicrobial studies of Mentha longifolia L. and Mentha piperita L. in Lower Himalaya. newlineTwo plant species were collected from four different sites (Giripul, Khairi, Bajhol and Nauni) newlinefor subsequent four months (April, May, June, July) and were used for morphological, newlineanatomical, biomass yield, phytochemical and antibacterial studies. Biomass yield results newlinerevealed that the maximum fresh and dry weight were found in July month in all the sites. newlineMorphological studies revealed that the stem length, no. of leaves and leaf area were found newlinemaximum in Giripul site and root length and fresh weight were found maximum in Nauni site. newlineThe anatomical features of the transverse sections of the M. longifolia (Giripul site) and M. newlinepiperita (Nauni site) leaves showed various structures and types of cells such as cuticle layer, newlineepidermal cells, trichomes, mesophyll cells, vascular bundles and other cells. Powder newlinemicroscopical study of M. longifolia (Giripul site) and M. piperita (Nauni site) powder newlinesamples showed the presence of different fragments of cells and tissues like epidermal cells, newlineparenchymatous cells, well arranged xylem and phloem vessels, fibres, tracheids, sclereids, newlinestarch grains, oil globules, tannin content, stomata, calcium oxalate crystals and numerous newlinetrichomes. The qualitative phytochemical analysis in methanolic leaf extracts revealed the newlinepresence of constituents such as carbohydrates, proteins, flavonoids, saponins, alkaloids, newlinetannins and phenolic compounds and the quantitative phytochemical estimation results newlinerevealed that the maximum quantity of phytochemicals were estimated in July month in both newlinethe Mentha plants of all four sites. On comparing M. longifolia site (having maximum newlinequantity of phytochemicals) with M. piperita (Nauni site), the results analysed that M. newlinelongifolia plants showed maximum phytochemicals content as compared to M. piperita. newlineOverall Giripul site revealed maximum quantity of phytochemicals in comparision to other newlinesites. Antimicrobial activity was performed against two bacteria: E. coli and S. aureus for newlinesubsequent four months. The maximum inhibition zones in each site were observed in the July newlinemonth against both the bacteria. Among the four different sites of two Mentha species, newlinexv newlinemaximum inhibition zones were reported in Giripul site which is followed by Nauni, Bajhol newlineand Khairi sites. The minimum inhibitory concentration (MIC) values i.e. 0.625 mg/ml newlineagainst E. coli and 1.25 mg/ml against S. aureus were found in Giripul, Bajhol and Nauni newlinesites in the June and July months. In comparision to the values of four different months, newlineextracts of both the Mentha species were found to be most active against E. coli and S. aureus newlinein July month. GC-MS analysis was performed in the methanolic leaf extracts of Giripul (M. newlinelongifolia) and Nauni (M. piperita) sites of July month. In M. longifolia, total 9 bioactive newlinecompounds were reported and out of 9, 7 compounds were found to be major compounds. M. newlinepiperita showed the presence of total 7 bioactive compounds and out of these 7, 5 compounds newlinewere major compounds. The present study revealed that among all the studied four months, newlineJuly month is better to get maximum biomass yield, extraction of maximum number of newlinephytoconstituents and antibacterial activity from the leaf extracts of both Mentha species. In newlinecomparision to both Mentha species, M. longifolia is more effective in phytochemicals and newlineantibacterial activity than M. piperita. newlineKey words: Biomass yield, Anatomy, Powder microscopy, Phytoconstituents, Antibacterial newlineactivity, GC-MS.