New Neolignan from Lycium barbarum

A comprehensive review on the ethnobotany, phytochemistry, pharmacology and quality control of the genus Lycium in China

The Lycium genus, perennial herbs of the Solanaceae family, has been an important source of medicines and nutrient supplements for thousands of years in China, where seven species and three varieties are cultivated. Among these, Lycium barbarum L. and Lycium chinense Mill., two "superfoods", together with Lycium ruthenicum Murr, have been extensively commercialized and studied for their health-related properties. The dried ripe fruits of the genus Lycium are well recognized as functional foods for the management of various ailments including waist and knee pain, tinnitus, impotence, spermatorrhea, blood deficiency and weak eyes since ancient times. Phytochemical studies have reported numerous chemical components in the Lycium genus, categorized as polysaccharides, carotenoids, polyphenols, phenolic acids, flavonoids, alkaloids and fatty acids, and its therapeutic roles in antioxidation, immunomodulation, antitumor treatment, hepatoprotection and neuroprotection have been further confirmed by modern pharmacological studies. As a multi-functional food, the quality control of Lycium fruits has also attracted attention internationally. Despite its popularity in research, limited systematic and comprehensive information has been provided on the Lycium genus. Therefore, herein, we provide an up-to-date review of the distribution, botanical features, phytochemistry, pharmacology and quality control of the Lycium genus in China, which will provide evidence for further in-depth exploration and comprehensive utilization of Lycium, especially its fruits and active ingredients in the healthcare field.

Lignans and Neolignans: Plant secondary metabolites as a reservoir of biologically active substances

Lignans and neolignans are plant secondary metabolites derived from the oxidative coupling of phenylpropanoids. Biological activity of these phenolic compounds ranges from antioxidant, antitumor (terminaloside P, IC₅₀ = 10 nM), anti-inflammatory, anti-neurodegenerative (schibitubin B, IC₅₀ = 3.2 nM) and antiviral (patentiflorin A, IC₅₀ = 14-23 nM) to antimicrobial. In addition, it was observed that several members of this group, namely enterolactone and its biochemical precursors also known as phytoestrogens, possess important protective properties. Most of these lignans and neolignans are presented in reasonable amounts in one's diet and thus the protection they provide against the colon and breast cancer, to name a few, is even more important to note. Similarly, neuroprotective properties were observed (schisanwilsonin G, IC₅₀ = 3.2 nM) These structural motives also serve as an important starting point in the development of anticancer drugs. Presumably the most famous members of this family, etoposide and teniposide, synthetic derivatives of podophyllotoxin, are used in the clinical treatment of lymphocytic leukemia, certain brain tumors, and lung tumors already for nearly 20 years. This review describes 413 lignans and neolignans which have been isolated between 2016 and mid-2018 being reported in more than 300 peer-reviewed articles. It covers their source, structure elucidation, and bioactivity. Within the review, the structure-based overview of compounds as well as the bioactivity-based overview of compounds are described.