Monnanda Somaiah Nalini

Endophytic Fungal Diversity in Medicinal Plants of Western Ghats, India

Endophytes constitute an important component of microbial diversity, and in the present investigation, seven plant species with rich ethnobotanical uses representing six families were analyzed for the presence of endophytic fungi from their natural habitats during monsoon (May/June) and winter (November/December) seasons of 2007. Fungal endophytes were isolated from healthy plant parts such as stem, root, rhizome, and inflorescence employing standard isolation methods. One thousand five hundred and twenty-nine fungal isolates were obtained from 5200 fragments. Stem fragments harbored more endophytes (80.37%) than roots (19.22%). 31 fungal taxa comprised of coelomycetes (65%), hyphomycetes (32%), and ascomycetes (3%). Fusarium, Acremonium, Colletotrichum, Chaetomium, Myrothecium, Phomopsis, and Pestalotiopsis spp. were commonly isolated. Diversity indices differed significantly between the seasons (). Species richness was greater for monsoon isolations than winter. Host specificity was observed for few fungal endophytes. UPGMA cluster analysis grouped the endophytes into distinct clusters on the basis of genetic distance. This study is the first report on the diversity and host-specificity of endophytic fungal taxa were from the semi evergreen forest type in Talacauvery subcluster of Western Ghats.

Fungal endophytes from the three-leaved caper, Crataeva magna (Lour.) DC. (Capparidaceae)

Fungal endophytes were isolated from Crataeva magna, a medicinal plant growing along the streams and rivers, constituting riparian vegetation in Karnataka, southern India. Fresh bark and twig pieces were used for the isolation using standard methods. Ninety-six endophytic fungal isolates were isolated from 800 bark and twig segments. Mitosporic fungi represented as a major group (85%) followed by zygomycetes (10%) and ascomycetes (5%). Bark samples contained more endophytes than twig samples. Verticillium, Nigrospora oryzae and Fusarium verticilloides were the dominant fungal endophytes.

Actinomycete endophytes from the ethno medicinal plants of southern India: antioxidant activity and characterization studies

Abstract Actinomycete endophytes (135) were isolated from Cajanus lineatus W. & A. (Maesen), Leucas ciliata Benth., Rauwolfia densiflora Benth. Ex. Hook. f. and Gomphostemma heyneanum Wall., four ethnomedicinal species of the southern region of the Western Ghats, a hot spot of biodiversity. The isolates were categorized into three supra generic groups on the basis of spore or aerial mycelial characters and confirmed by the partial 16S rRNA gene sequences. The actinomycete strains were subjected to fermentation and the ethyl acetate extracts were screened for the antioxidant assays. Streptomyces globosus (JQ926176) and Arthrobacter sp. (JQ926171) isolated from the stem fragments of R. densiflora and L. ciliata showed remarkable dose-dependent antioxidant activity in the in vitro assays. Among the screened extracts, S. globosus (IC50 88.2±1.03 μg/ml) and Arthrobacter sp. (IC50 = 97.6±1.97 μg/ml) exhibited high DPPH activity. S. globosus and Arthrobacter extracts contained a total antioxidant activity of 52.44±2.03 μM Fe (II)/g and 40.44±1.97 μM Fe (II)/g respectively. A significant correlation between the total phenolic content and total reducing power of S. globosus (R2=0.983) and Arthrobacter sp. (R2=0.987) extracts were noted. GC-MS characterization of the extracts revealed several compounds with antioxidant activity. S. globosus, S. hypolithicus, P. citrea and P. minatonensis are reported as endophytes for the first time in the ethnomedicinal plants.

Antioxidative properties of phenolic compounds isolated from the fungal endophytes of Zingiber nimmonii (J. Graham) Dalzell.

BackgroundThe microbes living in planta termed ‘endophytes’ is bestowed with the potential to produce bioactive substances. The aim of this investigation was focused on the isolation and molecular identification of the fungal endophytes from Zingiber nimmonii (J. Graham) Dalzell., an endemic medicinal plant species of the ‘Western ghats’, a hotspot location in southern India and characterization of the secondary metabolites responsible for the antioxidant and DNA protective capacity using chromatography and mass spectrometry techniques.MethodsEndophytic fungi were isolated and identified by sequencing the Internal Transcribed Spacer (ITS). The secondary metabolites were extracted with ethyl acetate and evaluated for the total phenolic, flavonoid and antioxidant capacities. The isolates with potential antioxidative property were further analyzed for the DNA protection ability and the presence of bioactive phenolic compounds by High Performance Liquid Chromatography (HPLC) and Electrospray Ionization-Mass Spectroscopy/Mass Spectroscopy (ESI-MS/MS) techniques.ResultsEndophytic fungi belonging to 11 different taxa were identified. The total phenolic content of the extracts ranged from 10.8±0.7 to 81.6±6.0 mg gallic acid equivalent/g dry extract. Flavonoid was present in eight extracts in the range of 5.2± 0.5 to 24.3±0.9 mg catechin equivalents/g dry extract. Bipolaris specifera, Alternaria tenuissima, Aspergillus terreus, Nectria haematococca and Fusarium chlamydosporum extracts exhibited a potentially high antioxidant capacity. Characterization of the extracts revealed an array of phenolic acids and flavonoids. N. haematococca and F. chlamydosporum extracts contained quercetin and showed DNA protection ability.ConclusionThis study is the first comprehensive report on the fungal endophytes from Z. nimmonii, as potential sources of antioxidative and DNA protective compounds. The study indicates that Z. nimmonii endophytes are potential sources of antioxidants over the plant itself.