Qi Zhi

Bio: Qi Zhi is an academic researcher from Southwest University. The author has contributed to research in topics: Oxidative stress & Oxygen radical absorbance capacity. The author has an hindex of 4, co-authored 6 publications receiving 38 citations.

Anti-aging effects of the fermented anthocyanin extracts of purple sweet potato on Caenorhabditis elegans.

Abstract: Anthocyanins have anti-inflammatory, anticarcinogenic and antioxidant properties and anti-aging effects as well as potential application as pigments. The metabolism of anthocyanins in fermented food has attracted increasing attention. However, the effect of lactic acid bacteria (LAB) fermentation on its anti-aging activity remains mostly unknown. The current study aimed to investigate the compositions, antioxidant activities and anti-aging effect of fermented purple sweet potato anthocyanins (FSPA) on aging Caenorhabditis elegans compared to raw purple sweet potato anthocyanins (PSPA). Results showed that anthocyanins were degraded into more bioavailable phenolic acids by Weissella confusa fermentation. PSPA and FSPA can extend the lifespan of C. elegans by 26.7% and 37.5%, respectively, through improving the activity of antioxidant enzymes as well as decreasing MDA content, ROS levels and lipofuscin accumulation. Pretreatment of the worms with PSPA and FSPA induced their potential to resist to thermal tolerance and oxidative stress, and FSPA exerted a higher anti-stress effect than PSPA. Moreover, FSPA supplementation upregulated the mRNA expressions of genes daf-16, hsp-16.2, sir-2.1, skn-1 and sod-3 and downregulated the expression of daf-2 in the nematodes, whereas PSPA only induced the increase in the expressions of sir-2.1, skn-1 and sod-3. Overall, FSPA can improve stress resistance and extend the lifespan of C. elegans by both insulin/IGF-1 signaling pathway and dietary restriction pathway, providing a theoretical basis for the application of PSPA in fermented food as functional pigments.

Extraction Optimization and Effects of Extraction Methods on the Chemical Structures and Antioxidant Activities of Polysaccharides from Snow Chrysanthemum (Coreopsis Tinctoria).

Abstract: In order to explore snow chrysanthemum polysaccharides (SCPs) as functional food ingredients and natural antioxidants for industrial applications, both microwave-assisted extraction (MAE) and ultrasonic-assisted extraction (UAE) were firstly optimized for the extraction of SCPs. Furthermore, the effects of conventional hot water extraction, UAE, and MAE on the chemical structures and antioxidant activities of SCPs were investigated. The maximum extraction yields of SCPs extracted by UAE (4.13 ± 0.24%) and MAE (4.26 ± 0.21%) were achieved at the optimized extraction parameters as follows: ultrasound amplitude (68%) and microwave power (500 W), ultrasound extraction time (21 min) and microwave extraction time (6.5 min), and ratio of liquid to raw material (42.0 mL/g for UAE and 59.0 mL/g for MAE). In addition, different extraction methods significantly affected the contents of uronic acids, the molecular weights, the molar ratio of constituent monosaccharides, and the degree of esterification of SCPs. SCPs exhibited remarkable DPPH (IC50 ≤ 1.702 mg/mL), ABTS (IC50 ≤ 1.121 mg/mL), and nitric oxide (IC50 ≤ 0.277 mg/mL) radical scavenging activities, as well as reducing power (≥ 80.17 ± 4.8 μg Trolox/mg), which suggested that SCPs might be one of the major contributors toward the antioxidant activities of snow chrysanthemum tea. The high antioxidant activities (DPPH, IC50 = 0.693 mg/mL; ABTS, IC50 = 0.299 mg/mL; nitric oxide, IC50 = 0.105 mg/mL; and reducing power, 127.79 ± 2.57 μg Trolox/mg) observed in SCP-M extracted by the MAE method might be partially attributed to its low molecular weight and high content of unmethylated galacturonic acids. Results suggested that the MAE method could be an efficient technique for the extraction of SCPs with high antioxidant activity, and SCPs could be further explored as natural antioxidants for industrial application.

Comparison of In Vitro and In Vivo Antioxidant Activities of Six Flavonoids with Similar Structures.

Abstract: The in vitro and in vivo antioxidant activities of six flavonoids with similar structures, including epicatechin (EC), epigallocatechin (EGC), procyanidin B2 (P), quercetin (Q), taxifolin (T), and rutin (R) were compared. The structures of the six flavonoids and their scavenging activities for 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) radicals were closely related. The flavonoids decreased serum contents of malondialdehyde (MDA) and nitric oxide (NO), and increased serum total antioxidative capacity (T-AOC), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) levels to different degrees in d-galactose-treated mice. The changes in mRNA expression of liver GSH-Px1, CAT, SOD1, and SOD2 by d-galactose were dissimilarly restored by the six flavonoids. Moreover, the six flavonoids differentially prevented the inflammatory response caused by oxidative stress by inhibiting interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α levels, and restoring IL-10 levels. These six flavonoids from two subclasses revealed the following antioxidant capability: P > EC, EGC > EC, Q > T, Q > R. Our results indicate that (1) the pyrogallol, dimerization, and C2=C3 double bonds of flavonoids enhanced antioxidant activity and (2) the C3 glycosylation of flavonoids attenuated antioxidant capacity.

Edible flowers as functional raw materials: A review on anti-aging properties

Abstract: Background Diet is a major determinant of aging and lifespan. Development and utilization of food resources with potential anti-aging activity have attracted increasing attention from researchers. Because of their peculiar flavour, aroma and colour, as well as enriched nutrients and phytochemicals, edible flowers have emerged as a new trend for human nutrition. More importantly, a growing body of evidence suggests flowers have potential effects against aging. However, these properties have yet to be systematically understood. Scope and approach In this review, we used comprehensive literature retrieval to summarize the major aspects of edible flowers’ anti-aging properties, including effects, active components, and applications. Relevant research articles published in English with no restrictions on publication date have been considered. Key findings and conclusions This review found evidence that edible flowers are promising raw materials for prevention or amelioration of skin aging, immunosenescence, neurodegeneration, and even extension of lifespan. Active ingredients in these flowers, including flavonoids, phenolic acids, carotenoids, phenylethanoid glycosides, polysaccharides, etc. may function through the inhibition of oxidative stress, inflammation, apoptosis and regulation of the insulin/insulin-like growth factor-1 (IIS) pathway. In addition to their use in traditional food and medicine, some flower extracts or main components have been developed for health care food or skin care products. These findings suggest that despite the partial restriction of harvest, storage and safety, edible flowers are worthy of further investigation to promote healthy aging.

Destabilisation and stabilisation of anthocyanins in purple-fleshed sweet potatoes: A review

Abstract: Background As a category of natural colourants, anthocyanins are abundant in purple-fleshed sweet potato (PFSP). Recently, anthocyanins from PFSP are proven to have multiple bioactivities, but they are liable to undergo discolouration and degradation upon thermal treatment, light exposure, oxidation, etc. Thus, the destabilisation/stabilisation of PFSP anthocyanins has received extensive attention from both academic and industrial views. Scope and approach This work aims to present an updated overview of the occurrence, destabilisation, and stabilisation of anthocyanins in purple-fleshed sweet potato varieties. Key findings and conclusions In total, forty-two anthocyanin monomers are found in PFSP, and they belong to the glycosylated and acylated derivatives of cyanidin, peonidin, pelargonidin, and delphinidin, with the first two predominating. Notably, PFSP anthocyanins were susceptible to destabilisation (degradation/discolouration) when exposed to acid/alkaline, heat, light, oxygen, ascorbic acid, sulfite, metal ions, and enzymes. Herein, the destabilising mechanism, the loss in food processing and the structure-stability relationship of PFSP anthocyanins were deeply discussed. More importantly, it was of high industrial significance that PFSP anthocyanins could be stabilised or protected by intramolecular or intermolecular copigmentation, encapsulation, and certain protective agents. Intramolecular copigmentation often occurred in acylated anthocyanin molecules, while phenolic acids, metal ions, polysaccharides, and proteins could serve as copigments in intermolecular copigmentation. When embedded in polysaccharide-based microcapsules and hydrogels, trapped in β-cyclodextrin cavities, and loaded in surfactant micelles, PFSP anthocyanins demonstrated enhanced stability. In addition, the replacement of ascorbic acid with its derivatives and the applications of antioxidants and enzyme inhibitors favoured the stabilisation of PFSP anthocyanins.