Chinese bayberry (Myrica rubra Sieb. et Zucc.) is a subtropical fruit tree native to China and other Asian countries, and culture of this Myricaceae plant has been recorded in Chinese history for more than 2000 years. Bayberry fruit is delicious with attractive color, flavor, and high economic value. Compared with other berries, bayberry fruit is a rich source of cyanidin-3-glucoside (C3G, e.g., 64.8 mg/100 g fresh weight in 'Biqi' cultivar), which accounts for at least 85 % of the anthocyanins in the fruit. Bayberry is also a plant with high medicinal value since different organs have been used historically as folk medicines. Research efforts suggest bayberry extracts contain antioxidants that exhibit bioactivities counteracting inflammation, allergens, diabetes, cancer, bacterial infection, diarrhea and other health issues. Bayberry compounds have been isolated and characterized to provide a better understanding of the chemical mechanisms underlying the biological activities of bayberry extracts and to elaborate the structure-activity relationships. As the identification of compounds progresses, studies investigating the in vivo metabolism and bioavailability as well as potential toxicity of bayberry extracts in animal models are receiving more attention. In addition, breeding and genetic studies of bayberry with high accumulation of health-benefiting compounds may provide new insight for the bayberry research and industry. This review is focused on the main medicinal properties reported and the possible pharmaceutically active compounds identified in different bayberry extracts.

In order to fully understand the variations of fruit quality-related phytochemical composition in Chinese bayberry (Myrica rubra Sieb. et Zucc.), mature fruit of 17 cultivars from Zhejiang and Jiangsu provinces was used for the investigation of fruit quality attributes, including fruit color, soluble sugars, organic acids, total phenolics, flavonoids, antioxidant capacity, etc. Sucrose was the main soluble sugar, while citric acid was the main organic acid in bayberry fruit. The content of total phenolics and total flavonoids were positively correlated with 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) antioxidant activity and 2,2ʹ-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activity. Five anthocyanidins, i.e., delphinidin–hexoside (Dp–Hex), cyanidin-3–O-galactoside (C-3–Gal), cyanidin-3–O-glucoside (C-3–Glu), pelargonidin-3–O-glucoside (Pg-3–Glu) and peonidin-3-O-glucoside (Pn-3–Glu), and seven flavonols compounds, i.e., myricetin-3-O-rhamnoside (M-3–Rha), myricetin deoxyhexoside–gallate (M-DH–G), quercetin-3-O-galactoside (Q-3–Gal), quercetin-3–O-glucoside (Q-3–Glu), quercetin-3–O-rhamnoside (Q-3–Rha), kaempferol-3–O-galactoside (K-3–Gal) and kaempferol-3–O-glucoside (K-3–Glu), were identified and characterized among the cultivars. The significant differences in phytochemical compositions among cultivars reflect the diversity in bayberry germplasm, and cultivars of good flavor and/or rich in various health-promoting phytochemicals are good candidates for future genetic breeding of bayberry fruit of high quality. In conclusion, our results may provide important information for further breeding or industrial utilization of different bayberry resources.

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