Phytochemical antimicrobial and genetic analysis of Acacia nilotica from different geographical regions of Himachal Pradesh North West Himalaya

Abstract

newline viii newlineABSTRACT newlineThe present study is mainly focused on the effects of seasonal and geographical changes on the quality and quantity of secondary metabolites of Acacia nilotica. The leaf samples of A. nilotica were collected from the six districts of Himachal Pradesh in three different seasons, i.e. summer (March-June), monsoon (July-October) and winter (November-February). The results of the qualitative phytochemical analysis revealed the presence of phlobatanins, reducing sugars, tannins, flavonoids, glycosides and steroids in all the samples in different seasons. The maximum alkaloid content, i.e. 81.20±1.70% was observed in the samples collected from Mandi district during winter season and least alkaloids i.e. 5.30±0.60% were present in the samples of Una district collected in summer season. newlineOverall, TPC (274.17±4.56 and#956;g GAE/g), TFC (146.90±3.04 and#956;g RU/g), total alkaloids (81.20±1.70 %), ascorbic acid content (1035.78±4.79 and#956;g ascorbate/g extract), catalase activity (999.79±4.79 units/mg protein) and GPx activity (888.04±4.79 units/mg protein) were found highest in samples collected from high altitude (1502 amsl) as compared to low altitude areas (369 amsl). The findings suggested that the percentage of phytochemicals showed significant variations seasonally as well as geographically. The ethanolic leaf extract of A. nilotica showed higher activities against Gram negative strains, i.e. E. coli and S. aureus as compared to the fungal strain. The maximum zone of inhibition (22 mm) was shown against E. coli by ethanolic leaf extract of A. nilotica L. (75mg/ml) in the samples of Bilaspur district. Extracts of A. nilotica were found almost ineffective against C. albicans except samples of Bilaspur district (15-16 mm). newlineFor RAPD analysis, 12 oligonucleotide decamer primers were used to amplify the genomic DNA from six samples of A. nilotica. Out of these, 7 primers generated RAPD fingerprints that revealed, 68 bands, in which 61 bands were found to be polymorphic. The size of amplified fragments ranged from 100 to 1500 bp. The highest percentage of polymorphism i.e. 100% was shown by OPN-20, OPN-16 and OPA-Y04 primers, whereas the lowest percentage of polymorphism i.e. 40% was shown by OPA-02. The genetic variations of the plant did not seem responsible for the amount of the phytochemical variance. The present study concluded that the newlineix newlinegeographical variables like seasons, geographical conditions and altitude have shown correlation with the accumulation of secondary metabolites in A. nilotica. newlineKeywords: Acacia nilotica, genetic variability, RAPD, phytochemicals