Bangladesh Journal of Pharmacology Volume: 13; Number 1; Year 2018 Cite this article as: Shoba S, Sasikumar K, Sathiavelu M. Isolation of isosativenetriol from endophytic fungus Cochliobolus spp. of Aerva lanata. Bangladesh J Pharmacol. 2018; 13: 57-58. Isolation of isosativenetriol from endophy- tic fungus Cochliobolus spp. of Aerva lanata Sir, Endophytic fungi produce variety of secondary meta- bolites with novel structures and some of these bio- active compounds possess interesting biological activi- ties. Consequently, there has been growing research interest in the plant–associated microorganisms and marine-associated microorganisms (sponges and algae). Novel secondary metabolites synthesized from the endophytic microorganisms were recognized as potential sources for exploitation in the field of medi- cine, agriculture and industry (Guo et al., 2008). Endo- phytic fungus was isolated from the medicinal plant Aerva lanata (family: Amaranthaceae) and identified as Cochliobolous spp. The genus Cochliobolus and its anamorphic spp. include around 55 species occurring all over the world and many Cochliobolus and its anamorphic species (Bipolaris, Curvularia) are pathogens of weeds and can successfully be applied as weed herbi -cides because the weeds and pathogens have co- evolved over a long period (Strobel et al., 1991). Secon- dary metabolites like Curvularides, cochlioquinones, anthraquinones, helminthosporol, helminthosporal, pre -helminthosporol and many other related metabo-lites have been reported from Cochliobolus strains. These compounds may have important pharmacological potentials, such as antifungal, anti-oxidant, antimicro- bial properties (Chomcheon et al., 2010). The whole plant of A. lanata was used for the treatment of hepa- titis, anticalculus, diuretic, demulcent, anthelmintic and antidiarrheal (Shoba and Mythili, 2017). Some of the phytochemicals from A. lanata (aervitrin, aervolanine, aervoside, amyrin, betulin, campesterol, canthin-6-one, 10-hydroxycanthin-6-one, chrysin, daucosterol, hentria- contane, narcissin, β-sitosterol, and syringic acid) were isolated and reported with biological activities (Vetrichelvan and Jegadeesan, 2002). The aim of this research was to isolate the secondary metabolite from the endophytic fungus Cochliobolus spp. and evaluation of antimycobacterial potential. The fungus used in this study was isolated from the leaves of A. lanata (Shoba and Mythili, 2017) and identified as Cochliobolus spp. (KY800380) on the basis of the rDNA internal transcribed spacer gene sequence. Three weeks old grown fungal cultured broth was filtered to remove fungal mycelium (matt). Methanol (250 mL) was added to a flask containing fungal mycelium and kept it overnight in a shaker. The matt extracted methanol was collected, concentrated, dried and stored at 4°C for further analysis (Shylaja and Sathiavelu, 2017). Isolation of bioactive metabolites from the matt methanolic extract was done using modified solvent–solvent fractionation (Sasikumar and Ghosh, 2017). The dried methanolic matt extract was sequentially partitioned with petroleum ether to produce a petroleum ether-soluble fraction (pink color). The obtained petroleum ether-soluble fraction was dried and washed with ethyl acetate followed by chloroform, acetone and methanol respectively. The ethyl acetate, chloroform, acetone and methanol-soluble fraction were dried and all dried fractions were washed with acetone. All the acetone soluble fractions were combined, dried and further purified with silica column (60-120 mesh) using an isocratic solvent of acetone (100%). The acetone eluted fraction was completely evaporated and subjected for spectral analysis. Isosativenetriol (1) was isolated as light pink color crystal (Figure 1) (yield: 50 mg) and the molecular formula was proposed as C15H24O3 based on HR-EIMS showing an ion at m/z 253.4900 (calculated for 252.1725). The FT-IR spectrum of compound (1) revealed a broad peak situated at 3292 cm-1 which was assigned to O-H stretching vibration. The peaks at 2926, 2854 cm-1 were assigned to C-H stretching vibrations of methyl group, respectively to asymmetric and symmetric stretching vibrations of methylene groups. At 1381cm-1 it was identified the C-H scissoring vibration, while at 947 cm-1 it was found the C-O stretching vibration. The rocking vibration of methyl group was easily detectable in the spectrum at 742 cm-1. 13C NMR (100 MHz, DMSO) spectrum revealed the presence of 15 carbons and among that showed three methyl groups. δ34.93 (C-1), δ31.36 (C-2), δ29.47 (C-3), δ34.12 (C-4), δ29.16 (C-5), δ69.75 (C-6), δ173.46 (C-7), δ51.61 (C-8), δ65.94 (C-9), δ33.94 (C-10), δ69.21 (C-11), δ24.95 (C-12), δ24.90 (C-13), δ63.08 (C-14) and δ22.55 (C -15). 1H NMR (DMSO, 500MHz): δ 1.492 (m, 2H, H-2), 1.508 (m, 2H, H-3), 2.179 (s, 1H, H-4), 3.432 (brs, 1H, H- 5), 2.267 (dd, J = 8.9, 5.2 Hz, H-8), 2.280 (m, 1H, H-9), 2.299 (m, 1H, H-10), 0.083 (d, J = 5.6 Hz, H3-10), 0.955 (s, 3H, H-12), 0.890 (s, 3H, H-13), 1.335 (s, 2H, H-14), 0.868 A Journal of the Bangladesh Pharmacological Society (BDPS) Bangladesh J Pharmacol 2018; 13: 57-58 Journal homepage: www.banglajol.info Abstracted/indexed in Academic Search Complete, Agroforestry Abstracts, Asia Journals Online, Bangladesh Journals Online, Biological Abstracts, BIOSIS Previews, CAB Abstracts, Current Abstracts, Directory of Open Access Journals, EMBASE/Excerpta Medica, Global Health, Google Scholar, HINARI (WHO), International Pharmaceutical Abstracts, Open J-gate, Science Citation Index Expanded, SCOPUS and Social Sciences Citation Index ISSN: 1991-0088; DOI: 10.3329/bjp.v13i1.34953 Letter to the Editor This work is licensed under a Creative Commons Attribution 4.0 International License. You are free to copy, distribute and perform the work. You must attribute the work in the manner specified by the author or licensor (s, 3H, H-15), 4.013 (s, 1H, OH-6), 4.051 (s, 1H, OH-9) and 4.041 (s, 1H, OH-10). The FT-IR and NMR data of compound 1 was identical to the published data of the isosativenetriol (sesquiterpenoids types) (Osterhage et al., 2002; Dorn and Arigoni, 1975) and the structure was shown in Figure 1. Isosativenetriol was isolated along with a number of similar structure metabolites from the Helminthosporium sativum (Dorn and Arigoni, 1975) and also been isolated from a marine algicolous isolate of Drechslera dematioi- dea, along with sesquiterpenoids derivatives and other metabolites (Osterhage et al., 2002). Isosativenetriol exhibits significant antimycobacterial potential with MIC of 25 µg/mL against M. tuberculosis H37Rv using microplate alamar blue assay (Sharma et al., 2014). The results were depicted in Table I. From the findings of the present study, it revealed that the isosativenetriol isolated from endophytic fungus Cochliobolus spp. will be a promising lead molecule for anti-microbial and antitubercular drug development. The authors thank the management of VIT University for providing VIT SEED GRANT for supporting and carrying out this research work. Sundaramoorthy Shoba, Kandasamy Sasikumar and Mythili Sathiavelu School of Biosciences and Technology, VIT University, Vellore 632014, Tamil Nadu, India. Corresponding author: email: smythili@vit.ac.in References Chomcheon P, Wiyakrutta S, Aree T, Sriubolmas N, Ngam- rojanavanich N, Mahidol C, Ruchirawat S, Kittakoop P. Curvularides A–E: Antifungal hybrid peptide–polyketides from the endophytic fungus Curvularia geniculata. Chem Eur J. 2010; 16: 11178-85. Dorn F, Arigoni D. Zwei neue Sesquiterpene mit Isosativan- gerust aus Helminthosporium sativum. Experientia 1975; 31: 753-54. Guo B, Wang Y, Sun X, Tang K. 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J Ethnopharmcol. 2002; 80: 103-07. 58 Bangladesh J Pharmacol 2018; 13: 57-58 Table I Antimycobacterial activity of isosativenetriol from Cochliobolus spp. Samples Minimum Inhibition Concentration (µg/mL) M. tuberculosis H37RV Isosativenetriol 25 Pyrazinamide 3.125 Ciprofloxacin 3.125 Streptomycin 6.25 Figure 1: Isolation of metabolite from Cochliobolus spp. A) Acetone soluble fraction; B) Dried acetone fraction (pink oily); C) Struc- ture of isosativenetriol (1) Figure 1 Isolation of metabolite from Cochliobolus spp A Acetone soluble fraction B Dried acetone fraction pink oily C Struc: Table I: DatePrinted: This article was downloaded by you on: Feb 20, 2018