Evaluation of the antioxidant and pro-oxidant properties of some phytotherapeutics used for the management of hyperlipidemia

Hyperlipidemia is major risk factor for cardiovascular diseases thus pharmacological treatment is the cornerstone of the approach for hyperlipidemia. However both patients and the scientific societies have an urge to search for natural products due to side effects of statins. Antioxidant and pro-oxidant effects of natural products have been studied in the literature. To the best of our knowledge, there is scarce data on simultaneous evaluation of antioxidant and pro-oxidant capacities of natural products with antihyperlipidemic effects. In this context, our study was designed to evaluate the antioxidant and pro-oxidant capacities of methanol extracts of cratageus flower-leaf, hibiscus flower, green tea, myrtle leaf and bergamot methanol extract, bergamot fruit juice. Commercial samples were studied, only natural sample was myrtle. The methods used to detect total phenolic and flavonoid content were Folin-Ciocalteu and aluminium chloride respectively. Antioxidant capacity was measured with three different methods; Iron (III) reduction capacity method, free radical scavenging capacity DPPH method, Trolox equivalent antioxidant capacity (TEAC) method. Hydroxyl radical scavenging activity method was used for the evaluation of pro-oxidant capacity. The highest total phenolic content was detected in natural myrtus leaf (146,22±4,62 mg GAE/g extract, p<0,05); the lowest was in hibiscus flower from the herbalist (42,30±1,05 mg GAE/g extract, p<0,05). The highest total flavonoid content was measured in green tea from the pharmacy (48,76±0,69 mg quercetin/g extract, p<0,05); the lowest was in the hibiscus flower from the herbalist (17,09±0,62 mg quercetin/g extract, p<0,05). Among the bergamot samples, filtered fruit juice had the highest total phenolic and flavonoid content (197,35±6,29 mg GAE/100 ml bergamot juice; 94,14±1,39 mg quercetin / 100 ml bergamot juice; p<0,05, respectively). The highest ferrum (III) reduction and TEAC values were measured in green tea (2,29±0,12 mM Trolox /mg extract; p<0,05; 2,32±0,07 mmol Trolox/mg extract, p<0,05 respectively). The lowest IC50 by DPPH method was identified in myrtus leaf from the pharmacy (6,95±0,08 µg/ml; p<0,01). The highest ferrum (III) reduction and TEAC and the lowest IC50 values by DPPH method were detected in filtered bergamot juice (2,94±0,031 mM Trolox /10µL fruit juice, 5,14±0,084 mmol Trolox, 10,561±0,17 µl respectively). Among all the herbal drug samples and the bergamot samples, green tea from the pharmacy and filtered lyophilized bergamot juice with 1mg/ml concentration were associated with the lowest hydroxyl radical scavenger activity (0,171±0,013 µM MDA equivalent, p<0,05; 0,144±0,015 µM MDA equivalent, p<0,05 respectively). Actually the lowest pro-oxidant capacity was measured in filtered bergamot juice (0,073±0,006 µM MDA equivalent) however, since the other bergamot samples were not liquid form any further analysis has not been done. In our study, filtered bergamot juice got the highest attention due to its high total phenolic and flavonoid content, antioxidant capacity and low pro-oxidant value. Furthermore another drug which has to get attention among all the herbal drug samples was green tea since it showed high total flavonoid content, antioxidant capacity and low pro-oxidant capacity. Our study results highlight the necessity of clarifying the value of bergamot and green tea in this field with further studies.