Panax ginseng is one of the most universally used herbal medicines in Asian and Western countries. Most of the biological activities of ginseng are derived from its main constituents, ginsenosides. Interestingly, a number of studies have reported that ginsenosides and their metabolites/derivatives-including ginsenoside (G)-Rb1, compound K, G-Rb2, G-Rd, G-Re, G-Rg1, G-Rg3, G-Rg5, G-Rh1, G-Rh2, and G-Rp1-exert anti-inflammatory activities in inflammatory responses by suppressing the production of proinflammatory cytokines and regulating the activities of inflammatory signaling pathways, such as nuclear factor-κB and activator protein-1. This review discusses recent studies regarding molecular mechanisms by which ginsenosides play critical roles in inflammatory responses and diseases, and provides evidence showing their potential to prevent and treat inflammatory diseases.

Since chronic inflammation can be seen in severe, long-lasting diseases such as cancer, there is a high demand for effective methods to modulate inflammatory responses. Among many therapeutic candidates, lignans, absorbed from various plant sources, represent a type of phytoestrogen classified into secoisolariciresionol (Seco), pinoresinol (Pino), matairesinol (Mat), medioresinol (Med), sesamin (Ses), syringaresinol (Syr), and lariciresinol (Lari). Lignans consumed by humans can be further modified into END or ENL by the activities of gut microbiota. Lignans are known to exert antioxidant and anti-inflammatory activities, together with activity in estrogen receptor-dependent pathways. Lignans may have therapeutic potential for postmenopausal symptoms, including cardiovascular disease, osteoporosis, and psychological disorders. Moreover, the antitumor efficacy of lignans has been demonstrated in various cancer cell lines, including hormone-dependent breast cancer and prostate cancer, as well as colorectal cancer. Interestingly, the molecular mechanisms of lignans in these diseases involve the inhibition of inflammatory signals, including the nuclear factor (NF)-κB pathway. Therefore, we summarize the recent in vitro and in vivo studies evaluating the biological effects of various lignans, focusing on their values as effective anti-inflammatory agents.

Flavonoids have been shown to have anti-oxidative effects, as well as other health benefits (e.g., anti-inflammatory and anti-tumor functions). Luteolin (3′, 4′, 5,7-tetrahydroxyflavone) is a flavonoid found in vegetables, fruits, flowers, and herbs, including celery, broccoli, green pepper, navel oranges, dandelion, peppermint, and rosemary. Luteolin has multiple useful effects, especially in regulating inflammation-related symptoms and diseases. In this paper, we summarize the studies about the immunopharmacological activity of luteolin on anti-inflammatory, anti-cardiovascular, anti-cancerous, and anti-neurodegenerative diseases published since 2018 and available in PubMed or Google Scholar. In this review, we also introduce some additional formulations of luteolin to improve its solubility and bioavailability.

The immune system is one of the most important parts of the human body and immunomodulation is the major function of the immune system. In response to outside pathogens or high inflammation, the immune system is stimulated or suppressed. Thus, identifying effective and potent immunostimulants or immunosuppressants is critical. Ginsenosides are a type of steroid saponin derived from ginseng. Most are harmless to the body and even have tonic effects. In this review, we mainly focus on the immunostimulatory and immunosuppressive roles of two types ginsenosides: the protopanaxadiol (PPD)-type and protopanaxatriol (PPT)-type. PPT-type ginsenosides include Rg1, Rg2, Rh4, Re and notoginsenoside R1, and PPD-type ginsenosides include Rg3, Rh2, Rb1, Rb2, Rc, Rd, compound K (CK) and PPD, which activate the immune responses. In addition, Rg1 and Rg6 belong to PPT-type ginsenosides and together with Rg3, Rb1, Rd, CK show immunosuppressive properties. Current explorations of ginsenosides in immunological areas are in the preliminary stages. Therefore, this review may provide some novel ideas to researchers who study the immunoregulatory roles of ginsenosides.

The skin is the main barrier between the body and the environment, protecting it from external oxidative stress induced by ultraviolet rays. It also prevents the entrance of infectious agents such as viruses, external antigens, allergens, and bacteria into our bodies. An overreaction to these agents causes severe skin diseases, including atopic dermatitis, pruritus, psoriasis, skin cancer, and vitiligo. Members of the flavonoid family include apigenin, quercetin, luteolin, and kaempferol. Of these, apigenin has been used as a dietary supplement due to its various biological activities and has been shown to reduce skin inflammation by downregulating various inflammatory markers and molecular targets. In this review, we deal with current knowledge about inflammatory reactions in the skin and the molecular mechanisms by which apigenin reduces skin inflammation.