Purification of kavalactones from Alpinia zerumbet and their protective actions against hydrogen peroxide-induced cytotoxicity in PC12 cells

Polyphenols in edible plant leaves: an overview of their occurrence and health properties

Edible plant leaves (EPLs) constitute a major renewable functional plant biomass available all year round, providing an essential source of polyphenols in the global diet. Polyphenols form a large family of antioxidant molecules. They protect against the harmful effects of free radicals, strengthen immunity and stimulate the body's natural defenses thanks to their antibacterial and antiviral functions. This study refers to phenolic compounds from 50 edible plant leaves divided into four categories: green leafy vegetables, underutilized leafy vegetables, leafy spices and leafy drinks. It provides data on the identification, occurrence and pharmacological functions of polyphenols contained in EPLs, and provides a better understanding of trends and gaps in their consumption and study. Certain EPLs, such as moringa (Moringa oleifera Lam.), tea (Camellia sinensis L.) and several leafy spices of the Lamiaceae family, reveal important characteristics and therapeutic potential. The polyphenol composition of EPLs makes them functional plants that offer relevant solutions in the fight against obesity, the management of food insecurity and the prevention of chronic diseases.

Anti-hypertensive and composition as well as pharmacokinetics and tissues distribution of active ingredients from Alpinia zerumbet

Alpinia zerumbet is a food flavor additive and a traditional medicine herb around the world. Several studies have reported that A. zerumbet has excellent effects on a variety of cardiovascular diseases, but its potential hypertensive applications, and pharmacokinetic features of main active substances have not been fully investigated. The mechanism of anti-hypertension with ethyl acetate extracts of A. zerumbet fruits (AZEAE) was evaluated by L-NNA-induced hypertensive rats and L-NAME-injured human umbilical vein endothelial cells (HUVECs). Blood pressure, echocardiographic cardiac index and H&E staining were used to preliminary evaluate the antihypertensive effect of AZEAE, the levels of TNF-α, IL-6, and IL-1β were evaluated by ELISA, and the proteins expression of IL-1β, IL-18, AGTR1, VCAM, iNOS, EDN1 and eNOS were also evaluated. In addition, isolation, identification, and activity screening of bioactive compounds were carried ou. Next, pharmacokinetics and tissues distribution of dihydro-5,6-dehydrokavain (DDK) in vivo were measured, and preliminary absorption mechanism was conducted with Caco-2 cell monolayers. AZEAE remarkably enhanced the state of hypertensive rats. Twelve compounds were isolated and identified, and five compounds were isolated from this plant for the first time. The isolated compounds also exhibited good resistance against injury of HUVECs. Moreover, pharmacokinetics and Caco-2 cell monolayers demonstrated AZEAE had better absorption capacity than DDK, and DDK exhibited differences in tissues distribution and gender difference. This study was the first to assess the potential hypertensive applications of A. zerumbet in vivo and vitro, and the first direct and concise study of the in vivo behavior of DDK and AZEAE.

Intrinsic Ability of the β‐Oxidation Pathway To Produce Bioactive Styrylpyrones

Naturally occurring α‐pyrones with biological activities are mostly synthesised by polyketide synthases (PKSs) via iterative decarboxylative Claisen condensation steps. Remarkably, we found that some enzymes related to the fatty acid β‐oxidation pathway in Escherichia coli, namely the CoA ligase FadD and the thiolases FadA and FadI, can synthesise styrylpyrones with phenylpropionic acids in vivo. The two thiolases directly utilise acetyl‐CoA as an extender unit for carbon‐chain elongation through a non‐decarboxylative Claisen condensation, thus making the overall reaction more efficient in terms of carbon and energy consumption. Moreover, using a cell‐free approach, different styrylpyrones were synthesised in vitro. Finally, targeted feeding experiments led to the detection of styrylpyrones in other species, demonstrating that the intrinsic ability of the β‐oxidation pathway allows for the synthesis of such molecules in bacteria, revealing an important biological feature hitherto neglected.

Rapid screening of neuroprotective components from Huang-Lian-Jie-Du Decoction by living cell biospecific extraction coupled with HPLC-Q-Orbitrap-HRMS/MS analysis

Huang-Lian-Jie-Du Decoction (HLJDD), a well-known traditional Chinese formulation, has been proved to exert neuroprotective effects, however, the bioactive components in HLJDD still remain to be elucidated. In the present study, a rapid and effective method involving live cell biospecific extraction and HPLC-Q-Orbitrap HRMS/MS was utilized to rapidly screen and identify the neuroprotective compounds from the HLJDD crude extract directly. Firstly, sixteen principal components in HLJDD crude extract were identified by HPLC-Q-Orbitrap HRMS/MS analysis. After co-incubation with PC12 cells, which have been validated as the key target cells for neurodegenerative diseases, seven compounds of them were demonstrated to exhibit binding affinity to the target cells. Furthermore, three representative compounds named baicalin, wogonoside, and berberine were subsequently verified to exert cytoprotective effects on PC12 cells injured by hydrogen peroxide via inhibiting oxidative stress and cell apoptosis, indicating that these screened compounds may possess a potential for the treatment of neurodegenerative diseases and were responsible, in part at least, for the neuroprotective beneficial effects of HLJDD. Taken together, our study provides evidence that live cell biospecific extraction coupled with LC-HRMS/MS technique is an efficient method for rapid screening potential bioactive components in traditional Chinese medicines.

Viewpoint: A Contributory Role of Shell Ginger (Alpinia zerumbet (Pers.) B.L. Burtt & R.M. Sm) for Human Longevity in Okinawa, Japan?

The longevity of the population in the Okinawa Islands of Japan has been ascribed to genetic factors and the traditional Okinawa cuisine, which is low in calories and high in plant content. This diet includes shell ginger (Alpinia zerumbet (Pers.) B.L. Burtt & R.M. Sm) of the ginger family (Zingiberaceae). Due to its local popularity, Alpinia zerumbet has become the subject of a good deal of study at the University of the Ryukyus in Okinawa. Personal local experience and review of the literature now suggest that culinary shell ginger may contribute to longevity among the population in Okinawa. This is supported by its abundant phytochemical content, with antioxidant and anti-obesity properties. The major bioactive phytochemicals are dihydro-5,6-dehydrokawain (DDK; 80-410 mg g^-1 fresh weight), 5,6-dehydrokawain (DK; ≤100 mg g^-1), and essential oils, phenols, phenolic acids, and fatty acids (≤150 mg g^-1 each). Further, Alpinia zerumbet extends the lifespan in animals by 22.6%. In conclusion, culinary shell ginger may significantly contribute to human longevity in Okinawa.

Dihydro-5,6-dehydrokavain (DDK) from Alpinia zerumbet: Its Isolation, Synthesis, and Characterization

Dihydro-5,6-dehydrokavain (DDK) is the major and most promising component of the tropical plant Alpinia zerumbet (shell ginger), a species of the ginger family Zingiberaceae. Alpinia zerumbet is known for its human use as a traditional herbal medicine, food, and dietary supplement. With its α-lactone ring, DDK belongs to the large chemical group of kavalactones, which are also found in kava (Piper methysticum), another herbal medicine; DDK is characterized by a double-bond linkage at positions 5,6 and the absence of a double-bond linkage at positions 7,8. This dissociates DDK from other kavalactones with their linkages at positions 7,8 and 5,6 that are both either completely saturated or unsaturated, or may have an unsaturated bond at the position 7,8 as well as a saturated bond at the position 5,6. DDK is easily identified and quantified by HPLC and GC. DDK contents in fresh leaves, stems and rhizomes range from 80 to 410 mg/g, requiring solvent extraction procedures to ensure high DDK yield. This is best achieved by hexane extraction from fresh rhizomes that were previously boiled in water, allowing DDK yields of up to 424 mg/g. Successful synthesis of DDK can be achieved by asymmetric pathways, whereas its simple chemical structure facilitates the synthesis of DDK derivatives by HCl hydrolysis. Thus, all synthesized products may be used for various commercial purposes, including the potential development of promising antiobesity pharmaceutical drugs, preparation of specific and safe dietary supplements, and use as effective natural herbicides or fungicides.