Tamarind shell is rich in flavonoids and exhibits good biological activities. In this study, we aimed to analyze the chemical composition of tamarind shell extract (TSE), and to investigate antioxidant capacity of TSE in vitro and in vivo. The tamarind shells were extracted with 95% ethanol refluxing extraction, and chemical constituents were determined by ultra-performance chromatography–electrospray tandem mass spectrometry (UPLC-MS/MS). The free radical scavenging activity of TSE in vitro was evaluated using the oxygen radical absorbance capacity (ORAC) method. The antioxidative effects of TSE were further assessed in 2,2-azobis (2-amidinopropane) dihydrochloride (AAPH)-stimulated ADTC5 cells and tert-butyl hydroperoxide (t-BHP)-exposed zebrafish. A total of eight flavonoids were detected in TSE, including (+)-catechin, taxifolin, myricetin, eriodictyol, luteolin, morin, apigenin, and naringenin, with the contents of 5.287, 8.419, 4.042, 6.583, 3.421, 4.651, 0.2027, and 0.6234 mg/g, respectively. The ORAC assay revealed TSE and these flavonoids had strong free radical scavenging activity in vitro. In addition, TSE significantly decreased the ROS and MDA levels but restored the SOD activity in AAPH-treated ATDC5 cells and t-BHP-exposed zebrafish. The flavonoids also showed excellent antioxidative activities against oxidative damage in ATDC5 cells and zebrafish. Overall, the study suggests the free radical scavenging capacity and antioxidant potential of TSE and its primary flavonoids in vitro and in vivo and will provide a theoretical basis for the development and utilization of tamarind shell.

Alcohol liver disease (ALD) is one of the leading outcomes of acute and chronic liver injury. Accumulative evidence has confirmed that oxidative stress is involved in the development of ALD. In this study, we used chick embryos to establish ALD model to study the hepatoprotective effects of tamarind shell exttract (TSE). Chick embryos received 25% ethanol (75 μL) and TSE (250, 500, 750 μg/egg/75 μL) from embryonic development day (EDD) 5.5. Both ethanol and TSE were administrated every two days until EDD15. Ethanol-exposed zebrafish and HepG2 cell model were also employed. The results suggested that TSE effectively reversed the pathological changes, liver dysfunction and ethanol-metabolic enzyme disorder in ethanol-treated chick embryo liver, zebrafish and HepG2 cells. TSE suppressed the excessive reactive oxygen species (ROS) in zebrafish and HepG2 cells, as well as rebuilt the irrupted mitochondrial membrane potential. Meanwhile, the declined antioxidative activity of glutathione peroxidase (GPx) and superoxide dismutase (SOD), together with the content of total glutathione (T-GSH) were recovered by TSE. Moreover, TSE upregulated nuclear factor erythroid 2—related factor 2 (NRF2) and heme oxyense-1 (HO-1) expression in protein and mRNA level. All the phenomena suggested that TSE attenuated ALD through activating NRF2 to repress the oxidative stress induced by ethanol.

Sweet potato has played an important role in human diets for centuries. Sweet potato is an excellent source of nutrients and natural health-promoting chemicals such as carotenoids, vitamin C, and polyphenols. In this article, we selected forty-eight sweet potato cultivars to evaluate the contents of proximate compositions, phytochemicals, and total antioxidative capacity (TAC). In addition, the sensory taste test was conducted as well. The concentrations of chemical constituents varied significantly among the 48 cultivars. The starch content ranged from 10.58 to 28.08. The protein concentration was between 2.00 and 12.16. A noticeable variability was found in vitamin C (8.1766.09mg100g⁻¹), total polyphenols (0.3213.82µgg⁻¹), and carotenoids (0.22559.70µgg⁻¹). 3,5-dicaffeoylquinic acid was the dominant phenolic acid derivative in all varieties, followed by chlorogenic acid. The content ranges of 3,5-dicaffeoylquinic acid and chlorogenic acid were 0.4192.18µg100g⁻¹ and 1.5963.98µg100g⁻¹, respectively. Remarkable DPPH (0.190.59µgg⁻¹) and ABTS⁺ (0.191.42µgg⁻¹) antioxidant activities were also observed in these sweet potatoes. TAC was related to vitamin C, carotenoids, total polyphenols, and caffeic acid derivatives. The purple flesh cultivars, especially Mianzishu-9, Jiheishu-1, and Qianshu-18-5-1, rich in protein, starch, and antioxidants, had immense potential to improve malnutrition and hidden hunger. The dark orange flesh cultivars Hongxiangjiao and Ziyunhongxinshu performed best in sensory taste evaluation, but the nutrients and antioxidant effects were ordinary. These cultivars were suitable for enriching the human food systems.