Telomerase activators from 20(27)-octanor-cycloastragenol via biotransformation by the fungal endophytes.

Affiliation

Duman S(1), Ekiz G(2), Yılmaz S(3), Yusufoglu H(4), Ballar Kırmızıbayrak P(5), Bedir E(6).
Author information:
(1)Department of Bioengineering, Faculty of Engineering, İzmir Institute of Technology, 35430 Urla-İzmir, Turkey.
(2)Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Near East University, Nicosia, Mersin 10, Turkey; Department of Bioengineering, Graduate School of Natural and Applied Sciences, Ege University, 35100 Bornova-İzmir, Turkey.
(3)Department of Bioengineering, Faculty of Engineering, University of Alanya Aladdin Keykubat, Antalya 07400, Turkey; Department of Biotechnology, Graduate School of Natural and Applied Sciences, Ege University, 35100 Bornova-İzmir, Turkey.
(4)Department of Pharmacognosy, College of Pharmacy, Prince Sattam Bin Abdulaziz University, 11942 Al-Kharj, Saudi Arabia.
(5)Department of Biochemistry, Faculty of Pharmacy, Ege University, 35100 Bornova-İzmir, Turkey.
(6)Department of Bioengineering, Faculty of Engineering, İzmir Institute of Technology, 35430 Urla-İzmir, Turkey. Electronic address: [Email]

Abstract

Cycloastragenol [20(R),24(S)-epoxy-3β,6α,16β,25-tetrahydroxycycloartane] (CA), the principle sapogenol of many cycloartane-type glycosides found in Astragalus genus, is currently the only natural product in the anti-aging market as telomerase activator. Here, we report biotransformation of 20(27)-octanor-cycloastragenol (1), a thermal degradation product of CA, using Astragalus species originated endophytic fungi, viz. Penicillium roseopurpureum, Alternaria eureka, Neosartorya hiratsukae and Camarosporium laburnicola. Fifteen new biotransformation products (2-16) were isolated, and their structures were established by NMR and HRESIMS. Endophytic fungi were found to be capable of performing hydroxylation, oxidation, ring cleavage-methyl migration, dehydrogenation and Baeyer-Villiger type oxidation reactions on the starting compound (1), which would be difficult to achieve by conventional synthetic methods. In addition, the ability of the metabolites to increase telomerase activation in Hekn cells was evaluated, which showed from 1.08 to 12.4-fold activation compared to the control cells treated with DMSO. Among the compounds tested, 10, 11 and 12 were found to be the most potent in terms of telomerase activation with 12.40-, 7.89- and 5.43-fold increase, respectively (at 0.1, 2 and 10 nM concentrations, respectively).