Biological Activities of Extracts from Loquat (Eriobotrya japonica Lindl.): A Review

Abstract

Loquat (Eriobotrya japonica Lindl.) is a subtropical fruit tree with high medicinal value native to China. Different organs of loquat have been used historically as folk medicines and this has been recorded in Chinese history for thousands of years. Research shows that loquat extracts contain many antioxidants, and different extracts exhibit bioactivity capable of counteracting inflammation, diabetes, cancer, bacterial infection, aging, pain, allergy and other health issues. Bioactive compounds such as phenolics and terpenoids have been isolated and characterized to provide a better understanding of the chemical mechanisms underlying the biological activities of loquat extracts. As the identification of compounds progresses, studies investigating the in vivo metabolism, bioavailability, and structure-activity relationships, as well as potential toxicity of loquat extracts in animal or cell models are receiving more attention. In addition, genetic studies and breeding of loquat germplasms for high contents of health-benefiting compounds may provide new insight for the loquat industry and research. This review is focused on the main medicinal properties reported and the possible pharmaceutically active compounds identified in different loquat extracts.

Keywords: Eriobotrya japonica Lindl.; bioactive compounds; bioactivities.

Figure 1

Structures of chemical compounds 1–14. 1: ursolic acid; 2: corosolic acid; 3: 3-O-cis-p-coumaroyltormentic acid; 4: 3-O-trans-p-coumaroyltormentic acid; 5: 3-epicorosolic acid; 6: euscaphic acid; 7: 1β-hydroxyeuscaphic acid; 8: oleanolic acid; 9: maslinic acid; 10: methyl arjunolate; 11: 2α,3α,23-trihydroxyolean-12-en-28-oic acid; 12: betulinic acid; 13: methyl chlorogenic acid; 14: tormentic acid.

Figure 2

Structures of chemical compounds 15–19. 15: nerolidol-3-O-α-l-rhamnopyranosyl(1,4)-α-l-rhamnopyranosyl(1,2)-[α-l-rhamnopyranosyl(1,6)]-β-d-glucopyranoside; 16: cinchonain Ib; 17: 3-epicorosolic acid methyl ester; 18: 2-α hydroxy-3-oxo urs-12-en-28-oic acid; 19: tormentic acid methyl ester.

Figure 3

Structures of chemical compounds 20–27. 20: epicatechin; 21: procyanidin B-2; 22: procyanidin C-1; 23: procyanidin oligomer; 24: δ-oleanolic acid; 25: 3-O-(E)-p-coumaroyl tormentic acid; 26: roseoside; 27: 2α-hydroxyursolic acid.

Figure 4

Structures of chemical compounds 28–33. 28: chlorogenic acid; 29: quercetin-3-sambubioside; 30: kaempferol-3-rhamnoside; 31: quercetin-3-rhamnoside; 32: cinchonain Ia; 33: arbutin.

Figure 5

Structures of chemical compounds 34–37. 34: α-hydroxyoleanolic acid; 35: arjunic acid; 36: 3-O-α-l-rhamnopyranosyl-(l→4)-α-l-rhamnopyranosyl-(1→2)-[α-l-(4-trans-feruloyl)-rhamnopyranosyl-(1→6)]-β-d-glucopyranosyl nerolidol; 37: ferulic acid.