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

Phytochemicals of Alpinia zerumbet: A Review

Alpinia zerumbet (Pers.) B.L.Burtt & R.M.Sm is a perennial plant of the Zingiberaceae family widely distributed in the subtropical and tropical areas of South America, Oceania, and Asia. Multiple plant parts of A. zerumbet have been traditionally used as medicinal sources, each with different clinical uses. These variations may arise from differences among the chemical components and/or accumulations of the active compounds in each part. Therefore, this review summarizes previous studies on the phytochemicals in A. zerumbet and reveals the similarities and differences among the chemical constituents of its multiple medicinal parts, including the leaves, rhizomes, fruits, seeds, and flowers. The results contribute to the scientific validation of the traditional understanding that A. zerumbet possesses different medicinal properties in each plant part. In addition, this review provides directions for further studies on the phytochemicals of this plant.

Chemical Composition and Potential Antimicrobial and Anti-Inflammatory Activities of Essential Oil from Fruits of Alpinia zerumbet (Pers.) B.L.Burtt & R.M.Sm

Alpinia zerumbet (Pers.) B.L.Burtt & R.M.Sm. was extensively used in traditional medicine for its several properties, but continuous investigation is needed to discover the properties of its essential oils (EOs). This work evaluated the properties of an EO obtained by steam distillation (named ESD) as well as extracts obtained by petroleum ether (named EP) both from Alpinia zerumbet fruits. Gas chromatography-mass spectrometry (GC-MS) was chosen to identify the composition, and eleven compounds were identified as the main components of the EO and EP of Alpinia zerumbet fruits. The antimicrobial properties were investigated by minimum inhibitory concentration (MIC) and the inhibition area. The results identified the differences in antimicrobial activities attributed to different extraction methods. Enzyme-linked immunosorbent assay (ELISA) and Western Blot (WB) assay were conducted to assess the anti-inflammatory effects of ESD. In conclusion, our study suggested that EO from Alpinia zerumbet fruits might be a prospective candidate for antimicrobial and anti-inflammatory therapy.

Treatment of Drug-Induced Liver Injury

Current pharmacotherapy options of drug-induced liver injury (DILI) remain under discussion and are now evaluated in this analysis. Needless to say, the use of the offending drug must be stopped as soon as DILI is suspected. Normal dosed drugs may cause idiosyncratic DILI, and drugs taken in overdose commonly lead to intrinsic DILI. Empirically used but not substantiated regarding efficiency by randomized controlled trials (RCTs) is the intravenous antidote treatment with N-acetylcysteine (NAC) in patients with intrinsic DILI by N-acetyl-p-aminophenol (APAP) overdose. Good data recommending pharmacotherapy in idiosyncratic DILI caused by hundreds of different drugs are lacking. Indeed, a recent analysis revealed that just eight RCTs have been published, and in only two out of eight trials were DILI cases evaluated for causality by the worldwide used Roussel Uclaf Causality Assessment Method (RUCAM), representing overall a significant methodology flaw, as results of DILI RCTs lacking RUCAM are misleading since many DILI cases are known to be attributable erroneously to nondrug alternative causes. In line with these major shortcomings and mostly based on anecdotal reports, glucocorticoids (GCs) and other immuno-suppressants may be given empirically in carefully selected patients with idiosyncratic DILI exhibiting autoimmune features or caused by immune checkpoint inhibitors (ICIs), while some patients with cholestatic DILI may benefit from ursodeoxycholic acid use; in other patients with drug-induced hepatic sinusoidal obstruction syndrome (HSOS) and coagulopathy risks, the indication for anticoagulants should be considered. In view of many other mechanistic factors such as the hepatic microsomal cytochrome P450 with a generation of reactive oxygen species (ROS), ferroptosis with toxicity of intracellular iron, and modification of the gut microbiome, additional therapy options may be available in the future. In summation, stopping the offending drug is still the first line of therapy for most instances of acute DILI, while various therapies are applied empirically and not based on good data from RCTs awaiting further trials using the updated RUCAM that asks for strict exclusion and inclusion details like liver injury criteria and provides valid causality rankings of probable and highly probable grades.

Synthesis of Chalcones Derivatives and Their Biological Activities: A Review

Chalcone derivatives are considered valuable species because they possess a ketoethylenic moiety, CO-CH=CH-. Due to the presence of a reactive α,β-unsaturated carbonyl group, chalcones and their derivatives possess a wide spectrum of antiproliferative, antifungal, antibacterial, antiviral, antileishmanial, and antimalarial pharmacological properties. Recent developments in heterocyclic chemistry have led to the synthesis of chalcone derivatives, which had been biologically investigated toward certain disease targets. The major aspect of this review is to present the most recent synthesis of chalcones bearing N, O, and/or S heterocycles, revealing their biological potential during the past decade (2010-2021). Based on a review of the literature, many chalcone-heterocycle hybrids appear to exhibit promise as future drug candidates owing to their similar or superior activities compared to those of the standards. Thus, this review may prove to be beneficial for the development and design of new potent therapeutic drugs based on previously developed strategies.

De novo biosynthesis of diverse plant-derived styrylpyrones in Saccharomyces cerevisiae

Plant styrylpyrones exerting well-established neuroprotective properties have attracted increasing attention in recent years. The ability to synthesize each individual styrylpyrone in engineered microorganisms is important to understanding the biological activity of medicinal plants and the complex mixtures they produce. Microbial biomanufacturing of diverse plant-derived styrylpyrones also provides a sustainable and efficient approach for the production of valuable plant styrylpyrones as daily supplements or potential drugs complementary to the prevalent agriculture-based approach. In this study, we firstly demonstrated the heterogenous biosynthesis of two 7,8-saturated styrylpyrones (7,8-dihydro-5,6-dehydrokavain (DDK) and 7,8-dihydroyangonin (DHY)) and two 7,8-unsaturated styrylpyrones (desmethoxyyangonin (DMY) and yangonin (Y)), in Saccharomyces cerevisiae. Although plant styrylpyrone biosynthetic pathways have not been fully elucidated, we functionally reconstructed the recently discovered kava styrylpyrone biosynthetic pathway that has high substrate promiscuity in yeast, and combined it with upstream hydroxycinnamic acid biosynthetic pathways to produce diverse plant-derived styrylpyrones without the native plant enzymes. We optimized the de novo pathways by engineering yeast endogenous aromatic amino acid metabolism and endogenous double bond reductases and by CRISPR-mediated δ-integration to overexpress the rate-limiting pathway genes. These combinatorial engineering efforts led to the first three yeast strains that can produce diverse plant-derived styrylpyrones de novo, with the titers of DDK, DMY and Y at 4.40 μM, 1.28 μM and 0.10 μM, respectively. This work has laid the foundation for larger-scale styrylpyrone biomanufacturing and the complete biosynthesis of more complicated plant styrylpyrones.

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Complete biosynthesis of plant styrylpyrones was firstly achieved in yeast.

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Yeast enzyme replaces unknown plant enzymes to produce 7,8-saturated styrylpyrones.

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CRISPR-based δ-integration led to stable styrylpyrone overproduction in rich medium.

Dietary supplementation of gingerols- and shogaols-enriched ginger root extract attenuate pain-associated behaviors while modulating gut microbiota and metabolites in rats with spinal nerve ligation

Neuroinflammation is a central factor in neuropathic pain (NP). Ginger is a promising bioactive compound in NP management due to its anti-inflammatory property. Emerging evidence suggests that gut microbiome and gut-derived metabolites play a key role in NP. We evaluated the effects of two ginger root extracts rich in gingerols (GEG) and shogaols (SEG) on pain sensitivity, anxiety-like behaviors, circulating cell-free mitochondrial DNA (ccf-mtDNA), gut microbiome composition, and fecal metabolites in rats with NP. Sixteen male rats were divided into four groups: sham, spinal nerve ligation (SNL), SNL+0.75%GEG in diet, and SNL+0.75%SEG in diet groups for 30 days. Compared to SNL group, both SNL+GEG and SNL+SEG groups showed a significant reduction in pain- and anxiety-like behaviors, and ccf-mtDNA level. Relative to the SNL group, both SNL+GEG and SNL+SEG groups increased the relative abundance of Lactococcus, Sellimonas, Blautia, Erysipelatoclostridiaceae, and Anaerovoracaceae, but decreased that of Prevotellaceae UCG-001, Rikenellaceae RC9 gut group, Mucispirillum and Desulfovibrio, Desulfovibrio, Anaerofilum, Eubacterium siraeum group, RF39, UCG-005, Lachnospiraceae NK4A136 group, Acetatifactor, Eubacterium ruminantium group, Clostridia UCG-014, and an uncultured Anaerovoracaceae. GEG and SEG had differential effects on gut-derived metabolites. Compared to SNL group, SNL+GEG group had higher level of 1'-acetoxychavicol acetate, (4E)-1,7-Bis(4-hydroxyphenyl)-4-hepten-3-one, NP-000629, 7,8-Dimethoxy-3-(2-methyl-3-buten-2-yl)-2H-chromen-2-one, 3-{[4-(2-Pyrimidinyl)piperazino]carbonyl}-2-pyrazinecarboxylic acid, 920863, and (1R,3R,7R,13S)-13-Methyl-6-methylene-4,14,16-trioxatetracyclo[11.2.1.0∼1,10∼.0∼3,7∼]hexadec-9-en-5-one, while SNL+SEG group had higher level for (±)-5-[(tert-Butylamino)-2'-hydroxypropoxy]-1_2_3_4-tetrahydro-1-naphthol and dehydroepiandrosteronesulfate. In conclusion, ginger is a promising functional food in the management of NP, and further investigations are necessary to assess the role of ginger on gut-brain axis in pain management.

Kavalactones isolated from Alpinia zerumbet (Pers.) Burtt. et Smith with protective effects against human umbilical vein endothelial cell damage induced by high glucose

A new kavalactone, 4'-hydroxyl dihydro-5, 6-dehydrokavain (1) was isolated from the petroleum ether partition of leaves of Alpinia zerumbet (Pers.) Burtt. et Smith, together with four known kavalactone dimers, rel-1,trans-3-bis-(4-methoxy-2-oxopyran-6-yl)-cis-2,trans-4-diphenyl cyclobutene (2), aniba dimer A (3), aniba dimer C (4), 6,6'-(3,4-diphenylcyclobutane-1,2-diyl)bis(4-methoxy-2H-pyran-2-one (5). The structure of compound 1 was characterized by its MS, 1D-NMR, and 2D-NMR data, and the structures of the known compounds were determined by comparison of their spectroscopic data with those reported by the literatures. The obtained compounds were evaluated for their protective activities on human umbilical vein endothelial cells (HUVECs) damaged by high glucose (35 mM, cell viability at 70.10%). Compounds 3 and 5 could increase the cell viability at the concentration of 12.5 μΜ (83.12%) and 25 μΜ (75.02%), whereas at the concentration of 12.5 μΜ, compounds 1, 2, and 4 didn't reverse cell damage (cell viability at 38.58%, 54.80% and 58.16%).

Alpinia zerumbet and Its Potential Use as an Herbal Medication for Atherosclerosis: Mechanistic Insights from Cell and Rodent Studies

BACKGROUND/AIMS

Alpinia zerumbet (Pers.) Burtt. et Smith has been used as a flavor additive in food and a traditional medicine for centuries, especially in Guizhou Province, China, and it prolongs people's lives with multiple beneficial effects. Thus, one of the aims of this review was to expound the chemical constituents of this plant, especially its fruits. Since cardiovascular diseases, including atherosclerosis, pose a health threat to humans, another aim was to expound the possible mechanisms of its potential use as an herbal medication for atherosclerosis.

METHODS

In this study, 10 reports are cited to expound the potential bioactive compounds. Moreover, 33 reports explain the antihypertensive and antiatherosclerotic effects of the plant by ameliorating inflammation and endothelial dysfunction, increasing vasodilation, improving hyperlipidemia, downgrading the glucose status, and working as an antioxidant.

RESULTS

A. zerumbetis rich in terpenes, essential oils, flavonoids, polyphenolics, and sterols. Pharmacological experiments showed that A. zerumbet has antioxidative and anti-inflammatory effects on the NF-κB signaling pathway and can ameliorate oxidative stress in the NOS-NO signaling pathway. Moreover, A. zerumbet demonstrates antihypertensive effects by accelerating vasorelaxant response and increasing 3T3-L1 intracellular cAMP, which has promising antiobesity properties, as well as hypolipidemic and anti-diabetic complication effects.

CONCLUSIONS

A. zerumbet has potential functions and applications in the prevention of atherosclerosis, but further studies are required before clinical trials.

Momilactones A and B Are α-Amylase and α-Glucosidase Inhibitors

Momilactones A (MA) and B (MB) are the active phytoalexins and allelochemicals in rice. In this study, MA and MB were purified from rice husk of Oryza sativa cv. Koshihikari by column chromatography, and purification was confirmed by high-performance liquid chromatography, thin-layer chromatography, gas chromatography-mass spectrometry, liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS), and ¹H and ¹³C nuclear magnetic resonance analyses. By in vitro assays, both MA and MB exerted potent inhibition on α-amylase and α-glucosidase activities. The inhibitory effect of MB on these two key enzymes was greater than that of MA. Both MA and MB exerted greater α-glucosidase suppression as compared to that of the commercial diabetic inhibitor acarbose. Quantities of MA and MB in rice grain were 2.07 ± 0.01 and 1.06 ± 0.01 µg/dry weight (DW), respectively. This study was the first to confirm the presence of MA and MB in refined rice grain and reported the α-amylase and α-glucosidase inhibitory activity of the two compounds. The improved protocol of LC-ESI-MS in this research was simple and effective to detect and isolate MA and MB in rice organs.

HPLC-ESI-MS/MS Profiling of Polyphenolics of a Leaf Extract from Alpinia zerumbet (Zingiberaceae) and Its Anti-Inflammatory, Anti-Nociceptive, and Antipyretic Activities In Vivo

Reactive oxygen species (ROS) have been linked to several health conditions, among them inflammation. Natural antioxidants may attenuate this damage. Our study aimed to investigate the chemical composition of a methanol leaf extract from Alpinia zerumbet and its possible antioxidant, anti-inflammatory, anti-nociceptive, and antipyretic effects. Altogether, 37 compounds, representing benzoic and cinnamic acid derivatives and flavonoids (aglycones and glycosides), were characterized. The extract showed substantial in vitro antioxidant effects, and inhibited both cyclooxygenase 1 (COX-1) and cyclooxygenase 2 (COX-2) in vitro, with a higher selectivity towards COX-2. It also inhibited 5-lipoxygenase (LOX) activity in vitro with nearly double the potency of zileuton, a reference 5-lipoxygenase (LOX) inhibitor. The extract exhibited anti-inflammatory effects against carrageenan-induced rat hind paw edema, and suppressed leukocyte infiltration into the peritoneal cavity in carrageenan-treated mice. Furthermore, it possessed antipyretic effects against fever induced by subcutaneous injection of Brewer's yeast in mice. Additionally, the extract demonstrated both central and peripheral anti-nociceptive effects in mice, as manifested by a decrease in the count of writhing, induced with acetic acid and an increase in the latency time in the hot plate test. These findings suggest that the leaf extract from Alpinia zerumbet could be a candidate for the development of a drug to treat inflammation and ROS related disorders.

Potential Therapeutic Benefits of Herbs and Supplements in Patients with NAFLD

Our aim is to review the efficacy of various herbs and supplements as a possible therapeutic option in the treatment and/or prevention of nonalcoholic fatty liver disease (NAFLD). We performed a systematic review of medical literature using the PubMed Database by searching the chemical names of many common herbs and supplements with “AND (NAFLD or NASH)”. Studies and medical literature that discussed the roles and usage of herbs and supplements in NAFLD and nonalcoholic steatohepatitis (NASH) from inception until 20 June 2018 were reviewed. Many studies have claimed that the use of various herbs and supplements may improve disease endpoints and outcomes related to NAFLD and/or NASH. Improvement in liver function tests were noted. Amelioration or reduction of lobular inflammation, hepatic steatosis, and fibrosis were also noted. However, well-designed studies demonstrating improved clinical outcomes are lacking. Furthermore, experts remain concerned about the lack of regulation of herbs/supplements and the need for further research on potential adverse effects and herb–drug interactions. In conclusion, preliminary data on several herbs have demonstrated promising antioxidant, anti-inflammatory, anti-apoptotic, and anti-adipogenic properties that may help curtail the progression of NAFLD/NASH. Clinical trials testing the safety and efficacy must be completed before widespread use can be recommended.

Isolation and Purification of Potent Growth Inhibitors from Piper methysticum Root

Piper methysticum (kava) root is known to possess promising weed suppressing activity. The present study was conducted to search for potent plant growth inhibitors from the root of this medicinal pepper plant. The ethyl acetate (EtOAc) extract exhibited the strongest reduction on growth of Raphanus sativus (radish) (IC₅₀ shoot and root growth = 172.00 and 51.31 µg/mL respectively) among solvent extracts. From this active extract, nine potent growth inhibitors involved in the inhibitory activities of P. methysticum root were isolated, purified and characterized by column chromatography (CC), gas chromatography-mass spectrometry (GC-MS), electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR). The six fractions purified by CC included two flavanones: 5-hydroxy-4′,7-dimethoxyflavanone (C1) and 5,7-dihydroxy-4′-methoxy-6,8-dimethylflavanone (matteucinol, C2) and six kavalactones: 5,6-dehydro-kavain (C3), a mixture of kavain and yagonin (C4), yagonin (C5) and dihydro-5,6-dehydrokavain, 7,8-dihydrokavain, dihydromethysticin and methysticin (C6). The amounts of 5-hydroxy-4′,7-dimethoxyflavanone, matteucinol, 5,6-dehydrokavain and yangonin were 0.76, 2.50, 2.75 and 2.09 mg/g dry weight (DW), respectively. The two flavanones C1 and C2 exhibited the strongest inhibition on shoot elongation (IC₅₀ = 120.22 and 248.03 µg/mL, respectively), whilst the two kavalactone mixtures C4 and C6 showed the highest suppression on root growth of R. sativus (IC₅₀ = 7.70 and 15.67 µg/mL, respectively). This study was the first to report the purification and inhibitory activities of the two flavanones 5-hydroxy-4′,7-dimethoxyflavanone and matteucinol in P. methysticum root. The isolated constituents from P. methysticum root including the flavanones C1 and C2 and the mixtures C4 and C6 may possess distinct modes of action on plant growth. Findings of this study highlighted that the combinations of hexane-ethyl acetate by 9:1 and 8:2 ratios successfully purified flavanones and kavalactones in P. methysticum root.

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.

An overview of chemical constituents from Alpinia species in the last six decades

Alpinia species is one of the most important genera of the Zingiberaceae family. Up to 2015, 544 compounds with various bioactivities were isolated, the major components are diarylheptanoids (143) and sesquiterpenoids (132).

5,6-Dehydrokawain from Alpinia zerumbet promotes osteoblastic MC3T3-E1 cell differentiation

Bone homeostasis is maintained by balancing bone formation and bone resorption, but an imbalance between them is associated with various bone-related diseases such as osteoporosis and rheumatoid arthritis. We found that 5,6-dehydrokawain (DK) and dihydro-5,6-dehydrokawain (DDK), which were isolated as promising compounds from Alpinia zerumbet rhizomes, promote differentiation of osteoblastic MC3T3-E1 cells. DK and DDK increased the alkaline phosphatase activity and matrix mineralization of MC3T3-E1 cells. DK exerts larger effects than DDK. The gene expression of runt-related transcription factor 2 and osterix, which are essential transcription factors in the early period of osteoblast differentiation, was significantly increased by DK treatment. The mRNA level of distal-less homeobox 5 was also enhanced by DK treatment, and DK activated the p38 mitogen-activated protein kinase pathway. Therefore, DK may have clinical potential for preventing osteoporosis, and could be considered as a potential anabolic therapeutic agent.

Changes in Chemical Composition, Total Phenolics and Antioxidant Activity of Alpinia (<i>Alpinia zerumbet</i>) Leaves Exposed to UV

Alpinia zerumbet (Pers.) B.L. Burtt. & R.M. Sm is an important perennial ginger plant in the tropics with various uses as foods, dietary supplement, cosmetics, essential oil production and traditional medicines. In this study, essential oils, phenolic acids, fatty acids, kavains, total phenols and antioxidant activity in A. zerumbet plants exposed to UV-C were investigated. Number and weights of essential oils increased rapidly from 1 to 3 days of exposure. Major extend of essential oils was recorded in methyl cinnamate and followed by benzyl acetone. The correspondence to the accumulation of palmitic acid was 15 folds, in contrast to the strong reduction of stearic quantity was 10 folds at 3 days of treatment. Changes in chemical components and antioxidant capacity in A. zerumbet are differed reversely between the exposure of UV-C and heavy toxic chemicals. The exposure of UV-C is beneficial for the increasing of essential oil production in A. zerumbet.

Changes in Chemical Composition, Total Phenolics and Antioxidant Activity of Alpinia (Alpinia zerumbet) Leaves Exposed to UV

Alpinia zerumbet (Pers.) B.L. Burtt. & R.M. Sm is an important perennial ginger plant in the tropics with various uses as foods, dietary supplement, cosmetics, essential oil production and traditional medicines. In this study, essential oils, phenolic acids, fatty acids, kavains, total phenols and antioxidant activity in A. zerumbet plants exposed to UV-C were investigated. Number and weights of essential oils increased rapidly from 1 to 3 days of exposure. Major extend of essential oils was recorded in methyl cinnamate and followed by benzyl acetone. The correspondence to the accumulation of palmitic acid was 15 folds, in contrast to the strong reduction of stearic quantity was 10 folds at 3 days of treatment. Changes in chemical components and antioxidant capacity in A. zerumbet are differed reversely between the exposure of UV-C and heavy toxic chemicals. The exposure of UV-C is beneficial for the increasing of essential oil production in A. zerumbet.