Antioxidant value and Antiproliferative Efficacy of Mitragynine and a Silane Reduced Analogue

Background: To investigate the antioxidant value and anticancer functions of mitragynine (MTG) and itssilane-reduced analogues (SRM) in vitro. Materials and
Methods: MTG and SRM was analyzed for their reducingpower ability, ABTS radical inhibition and 1,1-diphenyl-2-picryl hydrazylfree radicals scavenging activities.Furthermore, the antiproliferation efficacy was evaluated using MTT assay on K 562 and HCT116 cancer cell linesversus NIH/3T3 and CCD18-Co normal cell lines respectively.
Results: SRM and MTG demonstrate moderateantioxidant value with ABTS assay (Trolox equivalent antioxidant capacity (TEAC): 2.25±0.02 mmol trolox / mmoland 1.96±0.04 mmol trolox / mmol respectively) and DPPH (IC50=3.75±0.04 mg/mL and IC50=2.28±0.02 mg/mLrespectively). Both MTG and SRM demonstrate equal potency (IC50=25.20±1.53 and IC50= 22.19±1.06 respectively)towards K 562 cell lines, comparable to control, betulinic acid (BA) (IC5024.40±1.26). Both compounds showedconcentration-dependent cytototoxicity effects and exert profound antiproliferative efficacy at concentration >100 μM towards HCT 116 and K 562 cancer cell lines, comparable to those of BA and 5-FU (5-Fluorouracil).Furthermore, both MTG and SRM exhibit high selectivity towards HCT 116 cell lines with selective indexes of3.14 and 2.93 respectively compared to 5-FU (SI=0.60).
Conclusions: These findings revealed that the medicinaland nutitional values of mitragynine obtained from ketum leaves that growth in tropical forest of Southeast Asiaand its analogues does not limited to analgesic properties but could be promising antioxidant and anticancer orchemopreventive compounds.