Gynura procumbens aqueous extract alleviates nonalcoholic steatohepatitis through CFLAR-JNK pathway in vivo and in vitro

Current Knowledge Regarding Pharmacological Profile and Chemical Constituents of Gynura procumbens

Gynura procumbens (Lour.) Merr. is a well-known plant used in the folkloric medicine in tropical Asian countries. The plant is prevalently employed by traditional healers in the treatment of diabetes, cancer, hypertension, inflammation, fever and skin disorders. Several scientific studies reported that, Gynura procumbens possesses considerable therapeutic value for the development of emerging treatment options. The diverse pharmacological effects of this plant are attributed to its vast phytoconstituent content. Different chemical classes including alkaloids, flavonoids, phenolics, steroids, proteins and polysaccharides have been isolated from this plant. In this review, we tried to explore the different aspects of Gynura procumbens as an established medicinal plant. The data gathered here give an indication that the plant Gynura procumbens is a good natural source of chemical compounds with different types of pharmacological actions and these chemical compounds can be used as model for the development of de novo therapeutic agents.

Traditional uses, phytochemistry, pharmacology and toxicology of the genus Gynura (Compositae): A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Gynura cass., belonging to the tribe Senecoineae of the family Compositae, contains more than 40 accepted species as annual or perennial herbs, mainly distributed in Asia, Africa and Australia. Among them, 11 species are distributed in China. Many of the Gynura species have been used as traditional herbal medicines for the treatment of diabetes mellitus, rheumatism, eruptive fever, gastric ulcer, bleeding, abscesses, bruises, burning pains, rashes and herpes zoster infection in tropical Asia countries such as China, Thailand, Indonesia, Malaysia, and Vietnam. Some of the species have been used as vegetables, tea beverage or ornamental plants by the local people.

AIM OF THE STUDY

A more comprehensive and in-depth review about the geographical distribution, traditional uses, chemical constituents and pharmacological activities as well as safe and toxicity of Gynura species has been summarized, hoping to provide a scientific basis for rational development and utilization as well as to foster further research of these important medicinal plant resources in the future.

MATERIALS AND METHODS

A review of the literature was performed based on the existing peer-reviewed researches by consulting scientific databases including Web of Science, PubMed, Elsevier, Google Scholar, SciFinder and China National Knowledge Infrastructure.

RESULTS

Many of the Gynura species have been phytochemically studied, which led to the isolation of more than 338 compounds including phenolics, flavonoids, alkaloids, terpenoids, steroids, cerebrosides, aliphatics and other compounds. Pharmacological studies in vitro and in vivo have also confirmed the various bioactive potentials of extracts or pure compounds from many Gynura plants, based on their claimed ethnomedicinal and anecdotal uses, including antioxidant, anti-inflammation, anticancer, antidiabetic, antihypertension, antibacterial and other activities. However, pyrrolizidine alkaloids (PAs) pose a threat to the medication safety and edible security of Gynura plants because of toxicity issues, requiring the need to pay great attention to this phenomenon.

CONCLUSION

The traditional uses, phytochemistry and pharmacology of Gynura species described in this review demonstrated that these plants contain a great number of active constituents and display a diversity of pharmacological activities. However, the mechanism of action, structure-activity relationship, potential synergistic effects and pharmacokinetics of these components need to be further elucidated. Moreover, further detailed research is urgently needed to explain the mechanisms of toxicity induced by PAs. In this respect, effective detoxification strategies need to be worked out, so as to support the safe and reasonable utilization of Gynura plant resources in the future.

Antioxidant and Anti-Inflammatory Effects of Genus Gynura: A Systematic Review

Background: Gynura species have been used traditionally to treat various ailments, such as fever, pain, and to control blood glucose level. This systematic review critically discusses studies regarding Gynura species that exhibited antioxidant and anti-inflammatory effects, thus providing perspectives and instructions for future research of the plants as a potential source of new dietary supplements or medicinal agents. Methods: A literature search from internet databases of PubMed, Scopus, Science Direct, e-theses Online Service, and ProQuest was carried out using a combination of keywords such as "Gynura," "antioxidant," "anti-inflammatory," or other related words. Research articles were included in this study if they were experimental (in vitro and in vivo) or clinical studies on the antioxidant or anti-inflammatory effects of Gynura species and if they were articles published in English. Results: Altogether, 27 studies on antioxidant and anti-inflammatory effects of Gynura species were selected. The antioxidant effects of Gynura species were manifested by inhibition of reactive oxygen species production and lipid peroxidation, modulation of glutathione-related parameters, and enzymatic antioxidant production or activities. The anti-inflammatory effects of Gynura species were through the modulation of inflammatory cytokine production, inhibition of prostaglandin E2 and nitric oxide production, cellular inflammatory-related parameters, and inflammation in animal models. The potential anti-inflammatory signaling pathways modulated by Gynura species are glycogen synthase kinase-3, nuclear factor erythroid 2-related factor 2, PPARγ, MAPK, NF-κB, and PI3K/Akt. However, most reports on antioxidant and anti-inflammatory effects of the plants were on crude extracts, and the chemical constituents contributing to bioactivities were not clearly understood. There is a variation in quality of studies in terms of design, conduct, and interpretation, and in-depth studies on the underlying mechanisms involved in antioxidant and anti-inflammatory effects of the plants are in demand. Moreover, there is limited clinical study on antioxidant and anti-inflammatory effects of Gynura species. Conclusion: This review highlighted antioxidant and anti-inflammatory effects of genus Gynura and supported their traditional uses to treat oxidative stress and inflammatory-related diseases. This review is expected to catalyze further studies on genus Gynura. However, extensive preclinical data need to be generated from toxicity and pharmacokinetic studies before clinical studies can be pursued for their development into clinical medicines to treat oxidative stress and inflammatory conditions.

The Impacts of Herbal Medicines and Natural Products on Regulating the Hepatic Lipid Metabolism

The dysregulation of hepatic lipid metabolism is one of the hallmarks in many liver diseases including alcoholic liver diseases (ALD) and non-alcoholic fatty liver diseases (NAFLD). Hepatic inflammation, lipoperoxidative stress as well as the imbalance between lipid availability and lipid disposal, are direct causes of liver steatosis. The application of herbal medicines with anti-oxidative stress and lipid-balancing properties has been extensively attempted as pharmaceutical intervention for liver disorders in experimental and clinical studies. Although the molecular mechanisms underlying their hepatoprotective effects warrant further exploration, increasing evidence demonstrated that many herbal medicines are involved in regulating lipid accumulation processes including hepatic lipolytic and lipogenic pathways, such as mitochondrial and peroxisomal β-oxidation, the secretion of very low density lipoprotein (VLDL), the non-esterified fatty acid (NEFA) uptake, and some vital hepatic lipogenic enzymes. Therefore, in this review, the pathways or crucial mediators participated in the dysregulation of hepatic lipid metabolism are systematically summarized, followed by the current evidences and advances in the positive impacts of herbal medicines and natural products on the lipid metabolism pathways are detailed. Furthermore, several herbal formulas, herbs or herbal derivatives, such as Erchen Dection, Danshen, resveratrol, and berberine, which have been extensively studied for their promising potential in mediating lipid metabolism, are particularly highlighted in this review.