Medicinal foodstuffs. XII. Saponin constituents with adjuvant activity from hyacinth bean, the seeds of Dolichos lablab L. (1): Structures of lablabosides A, B, and C

Botany, traditional uses, phytochemistry, pharmacology, edible uses, and quality control of Lablab semen Album: A systematic review

ETHNOPHARMACOLOGICAL RELEVANCE

Lablab Semen Album (lablab), the white and dried mature fruit of Lablab purpureus in the Lablab genus of the Fabaceae family, is a renowned traditional medicinal herb with a long history of use in China. In Chinese medicine, lablab is often combined with other drugs to treat conditions such as weak spleen and stomach, loss of appetite, loose stools, excessive leucorrhoea, summer dampness and diarrhea, chest tightness, and abdominal distension.

MATERIALS AND METHODS

Comprehensive information on lablab was gathered from databases including Web of Science, Science Direct, Google Scholar, Springer, PubMed, CNKI, Wanfang, and ancient materia medica.

RESULTS

Lablab, a member of the lentil family, thrives in warm and humid climates, and is distributed across tropical and subtropical regions worldwide. Traditionally, lablab is used to treat various ailments, such as spleen and stomach weakness, loss of appetite, and diarrhea. Phytochemical analyses reveal that lablab is a rich source of triterpenoid saponins, glucosides, volatile components, polysaccharides, and amino acids. Lablab extracts exhibit diverse biological activities, including hypolipidemic, hypoglycemic, immunomodulatory, antioxidant, hepatoprotective, antitumoral, antiviral properties, and more. Besides its medicinal applications, lablab is extensively used in the food industry due to its high nutrient content. Additionally, the quality of lablab can be regulated by determining the levels of key chemical components pivotal to its medicinal effects, ensuring the herb's overall quality.

CONCLUSION

Lablab is a promising medicinal and edible plant ingredient with diverse pharmacological effects, making it a valuable ingredient for food, pharmaceuticals, and animal husbandry. However, it has inherent toxicity if not properly prepared. Additionally, some traditional uses and pharmacological activities lack scientific validation due to incomplete methods, unclear results, and insufficient clinical data. Thus, further in vivo and in vitro studies on its pharmacology, pharmacokinetics, and toxicology, along with clinical efficacy evaluations, are needed to ensure lablab's safety and effectiveness. As an important traditional Chinese medicine, lablab deserves more attention.

Saponins from Dolichos lablab seeds with anti-inflammatory activity

As one of a traditional Chinese medicine with dual applications in both medicinal treatment and dietary consumption, the mature seeds of D. lablab were reported to be rich in saponins and have a good effect on inflammatory related diseases. However, the substance basis for its anti-inflammatory activity remains unclear. Thus, a comprehensive phytochemical investigation on triterpenoid saponins from D. lablab seeds was carried out, resulting in the isolation and identification of twenty-one new triterpenoid saponins including dolilabsaponins A1-A4, B, C, D1-D3, E-M, N1, N2 and O (1-21) along with thirteen known analogs (22-34). Notably, the known saponins, 31, 32, and 34 were obtained from Leguminosae family for the first time. The 1H and 13C NMR data of saponins 24 and 28 were firstly reported here. Additionally, lipopolysaccharide (LPS)-stimulated RAW264.7 cells model was utilized to assess inhibitory activities of compounds 1-34 on nitric oxide (NO) production. The results revealed that compounds 1-3, 9, 10, 13-15, 18, 22, 23 and 28-34 significantly suppressed the elevation of NO levels in LPS-induced RAW264.7 cells at the concentration of 30 μM, exhibiting a concentration-dependent manner at 3, 10, and 30 μM. The results suggested that compounds 1-3, 9, 10, 13-15, 18, 22, 23, and 28-34 possessed potential anti-inflammatory activity. Further western blot assay demonstrated that 1, 9, 10, 13, 14, and 18 suppressed inflammatory response via down-regulated the expression levels of inflammatory factors, tumor necrosis factor-alpha and interleukin-6.

Application of plant-derived products as adjuvants for immune activation and vaccine development

Vaccines are one of the most important means to prevent and control the epidemic of infectious diseases. Commercial vaccines not only include corresponding antigens, but also need vaccine adjuvants. Immune adjuvants play an increasingly important role in the research, development and manufacture of vaccines. Adjuvants combined with antigens can improve the stability, safety and immune efficiency of vaccines. Some substances that can enhance the immune response have been found in nature(mainly plants) and used as adjuvants in vaccines to improve the immune effect of vaccines. These plant-derived immune adjuvants often have the advantages of low toxicity, high stability, low price, etc., providing more possibilities for vaccine development. We summarized and analyzed the advantages, application research, particulate delivery systems, existing problems and future research focus of botanical adjuvant. It is hoped to provide new ideas for the research and development of immune adjuvants in the future.

A review: structure-activity relationship between saponins and cellular immunity

Saponins, which exhibit many different biological and pharmacological activities, are present in a wide range of plant species and in some marine organisms. Notably, the researchers have found that saponins can activate the immune system in mammals. The strength of this function is closely related to the chemical structure of saponins. The present study of the structure-activity relationship suggests that aglycones, glycochains on aglycones and special functional groups of saponins affect the immune activity of saponins. This paper reviews the effects of different saponins on cellular immunity. As well as the structure-activity relationship of saponins. It is hoped that the information integrated in this paper will provide readers with information on the effects of saponins on cellular immunity and promote the further study of these compounds.

Future Directions for the Discovery of Natural Product-Derived Immunomodulating Drugs

Drug discovery from natural sources is going through a renaissance, having spent many decades in the shadow of synthetic molecule drug discovery, despite the fact that natural product-derived compounds occupy a much greater chemical space than those created through synthetic chemistry methods. With this new era comes new possibilities, not least the novel targets that have emerged in recent times and the development of state-of-the-art technologies that can be applied to drug discovery from natural sources. Although progress has been made with some immunomodulating drugs, there remains a pressing need for new agents that can be used to treat the wide variety of conditions that arise from disruption, or over-activation, of the immune system; natural products may therefore be key in filling this gap. Recognising that, at present, there is no authoritative article that details the current state-of-the-art of the immunomodulatory activity of natural products, this in-depth review has arisen from a joint effort between the International Union of Basic and Clinical Pharmacology (IUPHAR) Natural Products and Immunopharmacology, with contributions from a Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation number of world-leading researchers in the field of natural product drug discovery, to provide a "position statement" on what natural products has to offer in the search for new immunomodulatory argents. To this end, we provide a historical look at previous discoveries of naturally occurring immunomodulators, present a picture of the current status of the field and provide insight into the future opportunities and challenges for the discovery of new drugs to treat immune-related diseases.

Development of Broad-Spectrum Antiviral Agents-Inspiration from Immunomodulatory Natural Products

Developing broad-spectrum antiviral drugs remains an important issue as viral infections continue to threaten public health. Host-directed therapy is a method that focuses on potential targets in host cells or the body, instead of viral proteins. Its antiviral effects are achieved by disturbing the life cycles of pathogens or modulating immunity. In this review, we focus on the development of broad-spectrum antiviral drugs that enhance the immune response. Some natural products present antiviral effects mediated by enhancing immunity, and their structures and mechanisms are summarized here. Natural products with immunomodulatory effects are also discussed, although their antiviral effects remain unknown. Given the power of immunity and the feasibility of host-directed therapy, we argue that both of these categories of natural products provide clues that may be beneficial for the discovery of broad-spectrum antiviral drugs.

Triterpene Glycosides from the Seeds of Dolichos lablab

Two new triterpene glycosides (1 and 2), together with nine known triterpene glycosides (3-11), were isolated from the seeds of Dolichos lablab (Leguminosae). The structures of the new compounds were determined by spectroscopic analysis, including two-dimensional NMR spectroscopy, and chromatographic analysis of the hydrolyzed products. The isolated compounds did not show cytotoxicity against HL-60 human leukemia cells and HepG2 human hepatoma cells at sample concentrations of 20 µM.

Quantification of the constituents of the traditional Korea medicine, Samryeongbaekchul-san, and assessment of its antiadipogenic effect

Samryeongbaekchul-san (SBS) is a traditional herbal formula, which is used for the treatment of dyspepsia, chronic gastritis, and anorexia in Korea. To evaluate the quality of SBS decoction by quantifying its main constituents simultaneously using high-performance liquid chromatography coupled with photodiode array (HPLC–PDA) detection, and secondly to determine the antiadipogenic effect of SBS decoction. The main constituents in a 10-μL injection volume of the decoction were separated on Gemini C₁₈ and Luna NH₂ columns (both 250 mm × 4.6 mm, 5 μm) at 40 °C using a gradient of two mobile phases eluting at 1.0 mL/min. 3T3-L1 preadipocytes were differentiated into adipocytes for 8 days with or without SBS. After differentiation, accumulated triglyceride contents and leptin production were measured. The correlation coefficients of all constituents in a calibration curve were ≥0.9998 and showed good linearity in the tested concentration range after validation of the method established. The recovery of the four major compounds were 99.46–102.61% with intra- and interday precisions of 0.08–1.01% and 0.15–0.99%, respectively. The four compounds in the lyophilized SBS sample were detected up to 6.46 mg/g. SBS treatment of the differentiated adipocytes significantly inhibited lipid accumulation and leptin production without cytotoxicity. Optimized simultaneous determination of constituents by HPLC–PDA detection will help to improve quality assessment of SBS or related formulas. SBS has an antiadipogenic effect and further investigation to establish the mechanisms of action of its antiadipogenic effect is warranted.

Anti-Obesity Activities of Chikusetsusaponin IVa and Dolichos lablab L. Seeds

Obesity, a condition where excess body fat accumulates to the extent, causes a negative effect on health. Previously, we reported the extract of Dolichos lablab L. (DLL-Ex) inhibited high-fat diet (HFD)-induced increases in body weight and body fat mass and ameliorated increases in body weight. In the present work, we studyed the molecular mechanism for the inhibitory effect of DLL-Ex or Chikusetsusaponin IVa (CS-IVa), as isolated from Dolichos lablab L. (DLL) seeds extract, on adipocyte differentiation. We evaluated the effect of DLL-Ex, an anti-obesity agent, and CS-IVa, an active component of DLL-Ex, on 3T3-L1 cell differentiation via Oil red O assay and Q-PCR, along with their effects on CCAAT element binding protein alpha (C/EBPα), peroxisome proliferator-activated receptor gamma (PPARγ), fatty acid synthase (FAS), and fatty acid-binding protein 4 (FABP4) mRNA transcriptions. FAS and FABP4 protein expression levels after exposure to CS-IVa were also tested. The results showed that DLL-Ex and CS-IVa have potent inhibitory activity on adipocyte differentiation. Therefore, DLL and CS-IVa may be developed as a functional food material to treat obesity.

In vivo metabolomic interpretation of the anti-obesity effects of hyacinth bean (Dolichos lablab L.) administration in high-fat diet mice

SCOPE

The esoteric anti-obesity effects of hyacinth bean (Dolichos lablab L) have largely remained unexplored. Herein, we investigated the anti-obesity mechanisms of hyacinth bean compared to milk thistle, a natural herb employed for ameliorating obesity-related diseases, using high-fat diet (HFD) fed mice towards unfolding the perplexing mechanisms.

METHODS AND RESULTS

C57BL/6J mice were orally administered hyacinth bean (25 mg/kg/day) and milk thistle (100 mg/kg/day) for 9 weeks along with HFD. Intriguingly, a number of anti-obesity mechanisms indexed through clinical parameters, suppression in weight gains and liver steatosis were found similar to some disparity. Furthermore, the corresponding metabolic implications were studied through MS-based metabolite profiling, and using the Kyoto Encyclopedia of Genes and Genomes for metabolic pathways revealing that hyacinth bean or milk thistle administration effectively attenuates the HFD-induced lipid, glucose, and bile acid metabolism, with former specifically attenuates pyruvate-derived amino acids metabolism. Among them, valine, asparagine, and lysine displayed high correlation with blood clinical parameters.

CONCLUSION

A lower dose of hyacinth bean resulted in similar anti-obesity effects as milk thistle, as confirmed by both clinical and metabolomics analyses. Equivocally, we conjecture that hyacinth bean could be used as a potent anti-obesity herbal functional food.

Leguminous Plants in the Indonesian Archipelago: Traditional Uses and Secondary Metabolites

Indonesia is one of the richest countries with respect to plants resources. People from various ethnic, language, and religious groups have used the plants as alternative medicines, health foods and beverages for hundreds of years. To establish modern application for these understudied plant resources, ethnopharmacological data from more than 40 leguminous plants in Indonesia, spanning the western to the eastern parts of the Indonesian archipelago, were reviewed. In particular, bioactive secondary metabolites, including flavonoids, were described in detail to promote research into these plants as functional foods, nutraceuticals, and medicines.

Advances in saponin-based adjuvants

Saponins are natural glycosides of steroid or triterpene which exhibited many different biological and pharmacological activities. Notably, saponins can also activate the mammalian immune system, which have led to significant interest in their potential as vaccine adjuvants. The most widely used saponin-based adjuvants are Quil A and its derivatives QS-21, isolated from the bark of Quillaja saponaria Molina, which have been evaluated in numerous clinical trials. Their unique capacity to stimulate both the Th1 immune response and the production of cytotoxic T-lymphocytes (CTLs) against exogenous antigens makes them ideal for use in subunit vaccines and vaccines directed against intracellular pathogens as well as for therapeutic cancer vaccines. However, Quillaja saponins have serious drawbacks such as high toxicity, undesirable haemolytic effect and instability in aqueous phase, which limits their use as adjuvant in vaccination. It has driven much research for saponin-based adjuvant from other kinds of natural products. This review will summarize the current advances concerning adjuvant effects of different kinds of saponins. The structure-activity relationship of saponin adjuvants will also be discussed in the light of recent findings. It is hoped that the information collated here will provide the reader with information regarding the adjuvant potential applications of saponins and stimulate further research into these compounds.

Medicinal foodstuffs. XXV. Hepatoprotective principle and structures of ionone glucoside, phenethyl glycoside, and flavonol oligoglycosides from young seedpods of garden peas, Pisum sativum L

A new ionone glucoside, pisumionoside, a phenethyl glycoside, sayaendoside, and two acylated flavonol oligoglycosides, pisumflavonosides I and II, were isolated from the young seedpods of garden peas, Pisum sativum L., together with quercetin and kaempferol 3-O-(6-O-trans-p-coumaroyl)-beta-D-glucopyranosyl (1-->2)-beta-D-glucopyranosyl (1-->2)-beta-D-glucopyranosides and quercetin and kaempferol 3-sophorotriosides. The structures of pisumionoside, sayaendoside, and pisumflavonosides I and II were determined on the basis of chemical and physicochemical evidence, respectively. Quercetin 3-sophorotrioside, a principle component, was found to show protective effects on liver injury induced by D-galactosamine and lipopolysaccharide and by carbon tetrachloride in mice.

Bioactive oleanolic acid saponins and other constituents from the roots of Viguiera decurrens

The bisdesmoside oleanolic acid saponin, 3-0-(methyl-beta-D-glucuronopyranosiduronoate)-28-0-beta-D-glucopyranosyl-oleanolate along with nine known compounds (two diterpenic acids, one chromene, three triterpenes, one steroidal glycoside, and two monodesmoside oleanolic acid saponins), were obtained from Viguiera decurrens roots. The chemical structure of the bisdesmoside oleanolic saponin was determined by chemical and NMR spectral evidence. A mixture of monodesmoside saponins displayed cytotoxic activity against P388 and COLON cell lines (ED50= 2.3 and 3.6 microg/ml, respectively). Two of the known compounds showed insecticidal activity against the Mexican bean beetle larvae (Epilachna varivestis).

Medicinal foodstuffs. XXII. Structures of oleanane-type triterpene oligoglycosides, pisumsaponins I and II, and kaurane-type diterpene oligoglycosides, pisumosides A and B, from green peas, the immature seeds of Pisum sativum L

Two new oleanane-type triterpene oligoglycosides, pisumsaponins I and II, and two new kaurane-type diterpene oligoglycosides, pisumosides A and B, were isolated from the immature seeds (green peas) of Pisum sativum L. together with soyasaponin I, bersimoside I, dehydrosoyasaponin I, and their 6'-methyl esters. The structures of pisumsaponins and pisumosides were determined on the basis of chemical and physicochemical evidence as 22-O-malonylsoyasapogenol B 3-O-alpha-L-rhamnopyranosyl(1-->2)-beta-D-galactopyranosyl(1-->2)-beta-D-glucopyranosiduronic acid (22-O-malonylsoyasaponin I), sandosapogenol 3-O-alpha-L-rhamnopyranosyl(1-->2)-beta-D-galactopyranosyl(1-->2)-beta-D-glucopyranosiduronic acid, 17-O-beta-D-glucopyranosyl-6beta,7beta,13gamma,17-tetrahydroxy-19-kauranoic acid 19-O-beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranoside, and 6beta,7beta,13beta,17-tetrahydroxy-19-kauranoic acid 19-O-beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranoside, respectively.

Adjuvant and haemolytic activities of 47 saponins derived from medicinal and food plants

Adjuvant and haemolytic activities of 47 saponins purified from medicinal and food plants were examined. The compounds showed various levels of both adjuvant and haemolytic activities. Soyasaponins and lablabosides showed strong adjuvant activity but little haemolytic activity. Jujubosides showed strong adjuvant and haemolytic activities. Escins showed weaker adjuvant activity than the adjuvant-control, but strong haemolytic activity. Comparison of the functional groups of each saponin revealed that the acyl residue in saponin, the aldehyde group at carbon 4 in aglycone, and branched sugar chains attached to aglycone, were not essential for adjuvant activity. Furthermore, saponins with an acyl residue or oxide-ring moiety tended to show haemolytic activity. These results suggest that the adjuvant activity of saponins does not relate with haemolytic activity. It is considered that not only the functional groups themselves, but the overall conformation harmoniously consisting of such functional groups, affects adjuvant activity of saponins.