Characterization of the chemical composition of different parts of Dolichos lablab L. and revelation of its anti-ulcerative colitis effects by modulating the gut microbiota and host metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Ulcerative colitis (UC) is a non-specific inflammatory disease characterized by long duration and easy relapse. Dolichos lablab L. (DLL) belongs to the family Fabaceae, was listed in a famous Chinese medical classic, Compendium of Materia Medic, and described as possessing features that invigorate the spleen, alleviate dampness, provide diarrhea relief, and other effects. The DLL-dried white mature seeds (DS) and dried flower (DF), which hold significant medicinal value in China, were used in clinical prescriptions to prevent and treat UC. DS and DF have appeared in different editions of the Pharmacopoeia of the People's Republic of China from 1977 to 2020. However, their chemical composition, pharmacological effects, and mechanism of treating UC are unclear.

AIM OF THE STUDY

This study aimed to characterize the chemical composition of different parts of DLL (seeds and flowers), further explore their pharmacological effects, and elaborate its underlying mechanism of treating UC.

METHODS

The chemical composition of DS and DF crude polysaccharides (DSP and DFP) and ethanolic extracts (DSE and DFE) were characterized by high-performance anion-exchange chromatography (HPAEC), ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS), and gas chromatography-mass spectrometry (GC-MS). Then, based on the acute UC mice model, the pharmacodynamic effects were investigated by Western blotting, ELISA, and other methods. Finally, the 16S rRNA gene sequencing and metabonomic analysis were used to explore the regulatory effects of DS and DF on intestinal microbiota and host metabolism.

RESULTS

DSE and DFE inhibited the oxidative stress response, reducing proinflammatory factor production and maintaining intestinal barrier integrity in UC mice. The 16S rRNA gene sequencing and metabonomic analysis revealed that DS and DF treated UC by regulating the intestinal microbiota structure and reversing the abnormal metabolism of the host.

CONCLUSION

This study suggested that different parts of DLL (flowers and seeds) may be potential medicines for treating UC, which exert their therapeutic effects through various active ingredients and might contribute significantly to reducing the economic pressures and challenges of UC treatment worldwide.

Study on the interaction and functional properties of Dolichos lablab L. protein-tea polyphenols complexes

Tea polyphenols (TP) and plant proteins are significant materials in the food industry, the interactions between them are beneficial for their stability, functional properties, and biological activity. In this study, the mechanism and interaction between Dolichos lablab L. protein (DLP) obtained from nine treatments and three tea polyphenol monomers (EGCG, ECG, and EGC) were investigated. The results showed that the fluorescence of DLP was noticeably quenched and exhibited static quenching after the addition of polyphenols. DLP exhibited 1-2 binding sites for EGCG and ECG, but weakly binding to EGC (<1). The binding sites of DLP-TP were found to be in close proximity to the tyrosine residues, primarily interacting through hydrophobic interactions, van der Waals forces, and hydrogen bonds. The antioxidant capacity of DLP-TP compound was significantly improved after digestion. ECG showed a strong resistance to intestinal digestion. Compared with ECG (653.456 μg/mL), the content of free tea polyphenols of 20/40 kHz-ECG after digestion was 732.42 μg/mL. DLP-TP complexes significantly improved the storage stability, thermal stability, and bioaccessibility of tea polyphenols. The interaction between TP and DLP, as a protein-polyphenol complex, has great potential for application in preparing emulsion delivery systems due to their antioxidant activity and improved stability.

Safety assessment of saponins extract in Dolichos falcatus Klein: Subchronic study in Sprague-Dawley rats

ETHNOPHARMACOLOGICAL RELEVANCE

Dolichos falcatus Klein (DF), a Chinese Dai ethnic medicine popularly known as "Tuoyeteng" in Yunnan province of China, has been widely used in China to treat fracture, rheumatoid arthritis and soft tissue injuries for a long time. Our previous study showed that saponins in DF (DFS) ameliorated the gouty arthritis induced by MSU crystals in vivo and in vitro. The present study was carried out to evaluate the no-observed-adverse-effect level (NOAEL) of DFS.

MATERIALS AND METHODS

Sprague-Dawley rats (10/sex/group) were gavaged with DFS at dose level of 0, 50, 100 and 200 mg/kg body weight /day for 90-days.

RESULTS

DFS administration did not result in mortality or show treatment-related changes in clinical signs of toxicity, body weights gain or feed consumption. Similarly, in addition to slightly hemolytic anemia and gastrointestinal tract lesion in males of high-dose treatment group, no toxicologically significant treatment-related changes in hematological, clinical chemistry, urine analysis parameters, organ weights, and macroscopic and microscopic abnormalities were noted during the testing period.

CONCLUSION

The results of subchronic toxicity study support the NOAEL for DFS as 200 mg/kg/d in females and as 100mg/kg/d in males. These results provide an important reference for further DFS-related clinical trials or new drug exploration.

Dolichos falcata Klein attenuated the inflammation induced by monosodium urate crystals in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Dolichos falcata Klein (DF), a Chinese Dai ethnic medicine popularly known as "Tuoyeteng" in Yunnan province of China, has been widely used as a traditional herbal medicine for the treatment of fracture and beriberoid disease for a long time in China. The present study was carried out to investigate the anti-inflammatory activity and the bioactive chemical constituents of DF, and further to assess its possible mechanism on gouty arthritis in an animal model of the MSU crystals-induced gouty inflammation.

MATERIALS AND METHODS

The ethanol extract (EE) of DF at the doses of 10, 20 and 40 mg/kg was administered to the rats treated with MSU crystals to evaluate the anti-gouty arthritis effect. Subsequently, the components of EE were isolated and identified using classical methods. Phyto-chemical analysis of EE was further carried out by HPLC-DAD. Finally, the anti-inflammatory effect of EE and two isolated components were assessed using the MSU crystals-treated monocyte/macrophage cell line RAW 264.7 in vitro.

RESULTS

EE (10, 20 and 40 mg/kg) significantly attenuated the pain threshold value, the joint swelling degree, the inflammatory cell infiltration of articular tissue and the increased levels of pro-inflammatory cytokines in MSU crystals-treated rats. Moreover, doliroside A (DA) and medicagenic acid-3-O-β-D-glucopyranoside (MG) were isolated and identified from EE. The major components of EE, including DA, MG and other triterpenoids, were well confirmed by HPLC. A further study revealed that EE, DA and MG (10, 20, 40μg/mL) exhibited stronger inhibitory effects on the production of pro-inflammatory cytokines (including interleukin-1β, interleukin-6 and tumor necrosis factor-α) in MSU crystals-treated RAW 264.7 cells.

CONCLUSION

These findings indicate that the major triterpenoids present in DF have a remarkable effect on improving symptoms of acute gouty arthritis induced by MSU crystals through inhibiting the production of pro-inflammatory cytokines.

Effect of Dolichos biflorus on blood sugar and lipids in diabetic rats

Diabetes mellitus is a chronic disease characterized by hyperglycemia and dyslipidemia, which leads to severe morbid complications. In view of the effectiveness of conventional herbal adjutants the present study was taken to assess the anti-diabetic and anti-lipidemic effect of Dolichos biflorus. 32 healthy albino rats of either sex were randomly divided into 4 equal groups (I-IV) each having 8 rats. Group I, control rats received only vehicular fluid while Group II received only Dolichos biflorus for the experimental period of 30 days. Diabetes was induced in Group II and Group IV rats by single intravenous dose of STZ and confirmed on 3rd day with fasting blood sugar (FBS) more than 250 mg/dl. Group III diabetic rats, received vehicular fluid while Group IV diabetic rats received Dolichos biflorus in single dose of 300 mg/kg body weight/day intra-gastrically up to the experimental period of 30 days. FBS levels were assessed on 1st, 8th, 15th, 22nd and 30th day. On last day overnight fasted rats were sacrificed for drawing the sample for lipid profile from beating heart and harvested for pancreatic tissue histology. Data obtained showed that FBS levels were decreased significantly when Dolichos biflorus was given to diabetic rats from mean +/- SD values 362 +/- 63.36 to 118 +/- 38.55 with p value < 001. S cholesterol and S. triglyceride levels were also decreased significantly with P value < 001. It was concluded that Dolichos biflorus has anti-diabetic and anti-lipidemic effect at daily oral dose and can be used as an adjuvant for management of diabetes mellitus and its associated complications.

Litholytic property of Kulattha (Dolichous biflorus) vs potassium citrate in renal calculus disease: a comparative study

OBJECTIVE

Renal calculus disease is associated with recurrence after its surgical removal in large number of cases. Kulattha is acclaimed to have litholytic property in ayurvedic literature. We decided to compare the litholytic property of Kulattha with potassium citrate, an agent used to reduce stone recurrence in modern medicine.

METHODS

Forty seven patients with diagnosis of calcium oxalate renal calculi were taken in study. Twenty four patients received Kulattha (Group I) and 23 patients were given potassium citrate(Group II) for a period of 6 months. The size of renal calculi was studied by periodic ultrasound assessment in both groups.

RESULTS

Mean size of stone in group I at 0 month and at 6 month were 5.42 +/- 1.55 mm and 4.26 +/- 1.2 mm. mean size of stone in group II at 0 month and at 6 month was 6.46 +/- 3.08 mm and 4.64 +/- 1.40 mm. Statistical analysis showed that P value of less than 0.05 was seen in the first group from 0 to 6 month. There was no significant difference in the stone size within group II when the 3rd month and 6th month visit was compared with initial visit.

CONCLUSION

Kulattha can be used to reduce the recurrence of calcium oxalate stone and it is shown to have a better result than the use of conventional potassium citrate in such patients.

Therapeutic and pathogenetic animal models for Dolichos pruriens

The therapeutic and pathogenetic effects of Dolichos pruriens were evaluated using experimental models in rats. In the therapeutic experiment Wistar rats were housed in a heated environment (25+/-3 degrees C) to induce itch, and treated with ascending potencies D. pruriens (6 cH, 9 cH, 12 cH and 30 cH), each for 10 days. The positive control group received vehicle (ethanol 30% in water). The negative control group received no treatment and were kept at a standard temperature. In the pathogenetic experiment, all animals were kept at a temperature of 20+/-3 degrees C and treated for 30 consecutive days with D. pruriens 6 or 30 cH, or ethanol vehicle, or no treatment. The experiments were performed blind. The statistical analysis used Bartlett's test, followed by ANOVA/Tuckey-Krammer or Kruskal-Wallis/Dunn. The results point to the existence of therapeutic effects, with inhibition of the itching, skin lesions and fur thinning produced by heat, more evident in later observations, with the 9 12, and 30 cH potencies (Kruskal-Wallis/Dunn; P=0.001). No changes were observed in the other parameters, such as open field activity and laterality of the itching. In the pathogenetic experiment, no changes were observed in any parameters examined. We conclude that the proposed experimental model demonstrates the therapeutic effect of D. pruriens, but not its pathogenetic effects.

Duodenal ulcer prevalence: research into the nature of possible protective dietary lipids

The varying geographical prevalence of duodenal ulceration has suggested a relationship to staple diet. Previous experiments on animal peptic ulcer models showed that certain foods, particularly the lipid fraction, are ulceroprotective. This paper reports experiments on animal models further to investigate the nature of the protective substances in the most active lipid, that of horse gram. The free fatty acids and triglycerides, sterols, sterol esters and phospholipids from horse gram were extracted and tested for protective activity on rat peptic ulcer models: the pyloric ligation model which is chronic, involving 14 days pre-feeding, and two acute models using ethanol or cysteamine to induce ulceration. The results showed that sterol esters, but not sterols, were protective in the pyloric ligation model. Sterols were protective in the acute models using ethanol-induced and cysteamine-induced ulceration. Phospholipids were protective in both types of model. The free fatty acids and triglycerides gave no protection using the pyloric ligation model. The presence of sterols, sterol esters and phospholipids in the lipid fraction of foods in staple diets may account for the low prevalence of duodenal ulcer in certain geographical areas, despite a uniformly high prevalence of Helicobacter pylori infection.