Total phenolics, capsaicinoids, antioxidant activity, and α-glucosidase inhibitory activity of three varieties of pepper seeds

Abstract

Chopped pepper, a traditionally fermented condiment product in China, is widely consumed because of its good flavor. However, large amounts of byproduct, namely, chopped pepper seeds (CPS) are produced annually during the manufacture of chopped pepper product, and this material is generally classified as solid waste, which causes waste of resource. In this work, the total phenolics (TPC) and capsaicinoids content, antioxidant property, and αglucosidase inhibitory activity (GIA) of three varieties CPS (i.e., WPS, LPS, and BRPS) were assessed. The effects of solvents with different polarities, including 80% methanol, 80% acetone, and 80% ethanol, in extracting the bioactive compounds were also investigated. The results indicated that the studied CPS were rich in total phenolics and capsaicinoids with contents of 3,934-6,208 μg GAE/g dw and 1,052-3,692 μg/g dw, respectively. Three capsaicinoid compounds, namely, capsaicin, dihydrocapsaicin, and nordihydrocapsaicin, in the CPS were identified and quantified by HPLC. All CPS samples exhibited potent antioxidant property and GIA. Moreover, the different extraction solvents exhibited considerable influence on TPC, capsaicinoid content, antioxidant capacity, and GIA. Regardless of different polarities extraction solvents, BRPS had the highest level of phenolics, capsaicin, dihydrocapsaicin and nordihydrocapsaicin and exhibited the strongest antioxidant activity and GIA among the three varieties CPS studied. In practical applications, the use of 80% ethanol is recommended for the extraction of bioactive compounds from BRPS, because it is environment friendly. Positive correlations between phenolics, capsaicinoids, antioxidant activity, and GIA were observed by PCA and linear correlation analysis. Thus, CPS, especially BRPS, is abundant and can be a cheap source of natural antioxidants and anti-diabetic compounds, making it an interesting ingredient in the potential future development of nutraceuticals or functional food products and bringing great advantages for food and pharmaceutical industries, consumers, and producers.

Effects of Solid-State Fermentation with Eurotium cristatum YL-1 on the Nutritional Value, Total Phenolics, Isoflavones, Antioxidant Activity, and Volatile Organic Compounds of Black Soybeans

“…Furthermore, it was further found that 80% acetone extracts of BS or FBS showed the greatest TPC among the three solvent extracts, implying that 80% acetone was the best efficient solvent for extraction of phenolic compounds. This coincides with the studies reported by Zhao et al [47] and Liu et al [32] that 80% acetone displayed the best extraction capacity in extracting phenolic compounds from barley and pepper seeds, respectively. Moreover, it was interestingly noted that the TPC of FBS was significantly (p < 0.05) greater when compared with BS.…”

“…Previous research stated that the antioxidant potential of complex mixtures both depends on the antioxidant concentration and reactivity between reagents and the target compound [33]. Moreover, it has been reported that individual antioxidants can interact amongst themselves, which affected the antioxidant capacity of and creating synergistic, antagonistic, or even additive effects [32]. Furthermore, the presence of other bioactive compounds in the extract might also partly contribute to the observed results.…”

“…The FRAP values were reported as µmol Fe (II) equivalents/g DW sample. The RP of BS and FBS was conducted by adapting the procedure of Liu et al [32], and the results were expressed as µg VCE/g DW. The antioxidant capacity was also evaluated by chelating ability (CHA) on ferrous ions that were estimated following the procedure previously described by Xiao et al [33].…”

Enzyme-assisted extraction of anti-inflammatory compounds from habanero chili pepper (Capsicum chinense) seeds

“…In this study, TPCs in CPS extracts were higher than those reported by Gurnani et al ( 28 ) for n-hexane and chloroform extracts from Indian red CPSs with TPC contents of approximately 7.5-26.15 mg GAE/g. Liu et al ( 29 ) reported high total phenolic content in CPSs (3.93-6.21 mg GAE/g) using methanol, ethanol, or acetone but no information about the yield was described. Grimaldi et al characterized extracts from Capsicum annum fruits dried at different temperatures (45-65°C) and showed that the TPC decreased meanwhile the temperature increased from 6.9 mg GAE/g (45°C) to 6 mg GAE/g (65°C), in concordance with our results that the TPC equally decreased with the increasing of the temperature of extraction due the oxidation of phenolic compounds ( 30 ).…”

Recovery of Capsaicinoids and Other Phytochemicals Involved With TRPV-1 Receptor to Re-valorize Chili Pepper Waste and Produce Nutraceuticals

“…Beyond extraction yield, the bioactivity of the extracts must be considered since capsaicinoids are extracted along with other phytochemicals such as carotenoids and phenolics compounds. The bioactivity of compounds like capsaicinoids, carotenoids, and phenolic acids from waste materials of chili pepper includes antioxidant activity, α-glucosidase inhibitory activity or anti-inflammatory, and immune regulatory activity (Liu et al, 2020). Sricharoen et al (2017) found that the UAE produces an oleoresin rich in capsaicinoids, phenolics, carotenoids, flavonoids, and reducing sugars that could have a synergism to induce antioxidant and antidiabetic activity (Table 1).…”