Pharmacological activities of Hermannol (9-(7-methyloctyl)-9H-xanthene-2,3-diol), a new Xanthene derivative isolated from the roots of Hermannia geniculata Eckl. & Zeyh.

Abstract

Hermannia geniculata roots are commonly used in the treatment of several diseases in Sotho traditional medicine. A new xanthene derivative, Hermannol (9-(7-methyloctyl)-9H- xanthene-2,3-diol) was isolated from the roots of Hermannia geniculata. The structure was elucidated by analyses of their 1Dimensional and 2Dimensional Nuclear Magnetic Resonance, Mass Spectrometry and Infrared Spectroscopic data. In-vitro antioxidant, antidiabetic and antinflammatory evaluation of the compound using standard procedure showed that the compound has good radical scavenging capabilities against DPPH radicals with an IC50 value of 0.29 ± 0.011 mg/mL which is similar to the IC50 value 0.24 ± 0.020 mg/mL of the standard. Also, the metal-chelating properties of the compound is similar to the reference compound with their respective IC50 values (0.28 ± 0.074 and 0.029 ± 0.091) mg/mL. Inhibitory properties of hermannol against carbohydrate catabolizing enzymes, showed a lower inhibition of α-amylase with an IC50 value of 0.59 ± 0.086 mg/mL which is higher than standard drug (acarbose) with IC50 value of 0.43 ± 0.069 mg/mL. Also, it demonstrated higher inhibition of α-glucosidase enzyme with an IC50 value of 0.04 ± 0.002 mg/mL, this is lower than acarbose with an IC50 value of 0.16 ± 0.001 mg/mL. In addition, hermannol showed higher inhibition of 5-lipoxygenase enzyme than indomethacin (standard) with their respective IC50 values of (0.67 ± 0.042 and 1.07 ± 0.064) mg/mL. These results showed that hermannol, a new compound isolated from the root of H. geniculata may be used in the management of inflammation, oxidative stress-induced diseases and type 2 diabetes mellitus.