Antioxidant components and antioxidant/antiradical activities of desert truffle ( Tirmania nivea) from various Middle Eastern origins

Abstract

Dried desert truffles from Bahraini, Iranian, Moroccan and Saudi origins were examined for their antioxidant and antiradical activities using four analytical methods: ferric reducing ability (FRAP), DPPH, deoxyribose, and nitric oxide (NO). Chemical constituents contributing towards these activities were also investigated. Generally, these truffles possessed varying concentration of antioxidant chemicals averaging 9.6 ± 0.15, 12.0 ± 8.34, 1860 ± 361, 1328 ± 167 and 293 ± 32 mg/100 g dw, for ascorbic, anthocyanins, total esterified phenolics, total free phenolics and total flavonoids, respectively; total carotenoids averaged 681 ± 245 g/100 g dw. Dried truffles also varied with regard to their antioxidant and antiradical activities. The FRAP value averaged 15.41 ± 3.51 mmol/100 g dw. Antiradical activity measured as percent inhibition of DPPH quenching averaged 30.6 ± 12.97% and EC 50 of 0.55 ± 0.38 mg. The average EC 50 of NO scavenging activity was 159.4 ± 69.3 μg, whereas the average percent inhibition of deoxyribose degradation was 55.9 ± 30.1%. The Iranian truffles yielded the highest in several variables, whereas the Moroccan truffles possessed the lowest values of many variables among the four tested samples. Significant correlation was established between total and free phenolics and FRAP values, and between flavonoids and percent radical inhibition using DPPH, NO and deoxyribose assays.