Catechin rich butanol fraction extracted from Acacia catechu L. (a thirst quencher) exhibits immunostimulatory potential

Antioxidant, urobactericidal and antibiotic modulating activity of the methanolic extract of the stem and resin of Acacia catechu (L.f.) Willd

BACKGROUND

Emergence of multidrug resistant pathogens has opened new vistas for novel drug discovery or combinatorial drug surveillance, often in form of some natural products, which is considered to be cheap and safe. In this study, the urobactericidal activity of the methanolic extract of the stem and resin of Acacia catechu (L.f.) Willd (Fabaceae) was explored against five uropathogenic bacterial strains i.e. Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Proteus vulgaris and Staphylococcus aureus.

METHODS

Varieties of antibacterial (disc diffusion, agar well diffusion, modified agar well diffusion) and antioxidant assays (DPPH and OH free radical scavenging assay) were tried to prove the efficacy of stem and resin extracts of A. catechu and to compare their urobactericidal and free radical scavenging properties.

RESULTS

Phytochemical analysis envisaged that the stem and resin contained phytoconstituents like alkaloids, phenols, tannins, proteins, glycosides, flavonoids, steroids and terpenoids, which were reported to have excellent antioxidant and antibacterial activities. The total phenolic contents of the methanolic extract of A. catechu stem (ACs) and A. catechu resin (ACr) were calculated as 37.74 ± 0.023 and 51.98 ± 0.011 mg/g Gallic Acid equivalents. The total flavonoid contents of methanolic extract of ACs and ACr were calculated to be 71.33 ± 0.004 and119.6 ± 0.010 mg/g Rutin equivalent. ACs had IC50 value of 93.68 ± 0.71; 90.92 ± 0.54 µg/mL and ACr had 79.21 ± 0.54; 85.74 ± 0.61 µg/mL in comparison to an IC50 value of 72.33 ± 1.20; 66.96 ± 0.61 µg/mL for standard Ascorbic acid in the DPPH and hydroxyl free radical scavenging assay. Phytocompounds present in both ACs and ACr were proved to have improved the urobactericidal efficacies of conventional antibiotics especially against the E. faecalis and E. coli, the prime etiological agents of uropathogenesis.

CONCLUSION

Our results indicated the excellent urobactericidal effects of the stem and resin extracts of a least explored natural remedy against uropathogens, which will be beneficial for treating urinary tract infections and augmenting the quest for novel therapies in future for uropathogenesis.

Evaluation of the antidiarrheal activity of the 80% hydromethanolic crude extract and solvent fractions of Terminalia brownii Fresen (Combretaceae) leaves in Swiss Albino mice

Background

Although diarrhea is a preventable disease, it continues to have a significant impact on global health, with the burden being much greater in Sub-Saharan Africa. Medicinal plants represent affordable and locally available resources to address many diseases, including diarrhea. Thus, this study aimed to investigate the antidiarrheal activities of the 80% hydromethanolic crude extract and solvent fractions of Terminalia brownii Fresen (Combretaceae) leaves in Swiss Albino mice.

Methods

This study was carried out by administering the 80% hydromethanolic crude extract and solvent fractions from the crude extract, including the n-hexane fraction (NHF), ethyl acetate fraction (EAF), and aqueous fraction (AF) at doses of 100 mg/kg, 200 mg/kg, and 400 mg/kg, respectively, to the mice. The effects of these extracts and solvent fractions on reducing/delaying diarrhea were compared with the impact of the solvent used for reconstitution and a standard drug (loperamide 3 mg/kg or atropine 5 mg/kg), as well as with each other.

Results

The hydromethanolic crude extract and ethyl acetate fraction at all tested doses significantly reduced wet defecation (P < 0.05). In addition, total defecation was significantly reduced at a dose of 200 mg/kg (P < 0.05) and 400 mg/kg (P < 0.001) of the crude extract and ethyl acetate fraction at all tested doses (P < 0.01. The aqueous fraction at 200 mg/kg and 400 mg/kg and the n-hexane fraction at 400 mg/kg (P < 0.05) significantly inhibit wet and total defecation. Likewise, in the enteropooling test, the crude extract and ethyl acetate fractions showed a significant reduction in the weight and volume of intestinal contents at a dose of 200 mg/kg (P < 0.05) and 400 mg/kg (P < 0.05). Castor oil-induced intestinal motility was significantly reduced (p < 0.001) by the crude extract and ethyl acetate fractions at all tested doses.

Conclusion

The result from this study suggests significant antidiarrheal activity of Terminalia brownii leaves, which validates its traditional use. The 80% hydromethanolic crude extract and ethyl acetate solvent fractions of Terminalia brownii Fresen leaves have shown better antidiarrheal activity.

Antimicrobial and antiviral evaluation of compounds from Holoptelea integrifolia: in silico supported in vitro study

Holoptelea integrifolia, also known as the Indian Elm Tree, has been used in Ayurvedic medicine for its medicinal properties. In this study, two biologically active metabolites, 5(6) dihydrostigmast 22en 3-O-β-glucoside (DHS) and 1-O-eicosanoyl glycerol-2'-O-β-galactouronic (EGG), were isolated for the first time from the n-butanol fraction of H. integrifolia using a chromatographic technique and identified by NMR, and HRESI-MS. The antiviral and multidrug-resistant activities of these metabolites were evaluated as well as the n-butanol fraction. The n-butanol fraction of H. integrifolia exhibited weak antiviral effects, but DHS and EGG demonstrated significant antiviral activity against herpes simplex type-1 (HSV-1) and Coxsackie (CoxB4) viruses. Both metabolites showed lower IC50 values than the standard antiviral drug acyclovir, indicating their potency in inhibiting viral replication. EGG showed potent antiviral activity with minimal cytotoxicity at the highest concentration tested, presenting a selectivity index (SI) of 18.18 and 15.58 against HSV-1 and CoxB4 viruses, respectively. A preliminary assessment of the antibacterial activity of the n-butanol fraction and metabolites revealed that DHS had the highest inhibitory potency against drug-resistant strains, including MRSA and Carbapenem-resistant Klebsiella pneumonia. It also exhibited significant inhibitions against Fluconazole-resistant Candida albicans and ESBL - Escherichia coli. DHS displayed the lowest minimum inhibitory concentration (MIC) values, indicating its superiority as an antibacterial agent compared to EGG and the n-butanol fraction. Molecular docking analysis confirmed the antiviral and antibacterial actions of DHS and EGG by demonstrating their strong binding.

Modulation of immunological responses by aqueous extract of Datura stramonium L. seeds on cyclophosphamide-induced immunosuppression in Wistar rats

BACKGROUND

Datura stramonium L. (Solanaceae) is used traditionally in west Africa to treat asthma, epilepsy, rheumatoid arthritis, filariasis microbial infections and conjunctivitis. This study investigated the immunomodulatory effects of aqueous seed extract of D. stramonium L. (ASEDS) on Wistar rats.

METHODS

Thirty Wistar albino rats (180-200 g) were randomized into 6 groups (n = 5). Group 1 received distilled water only. Rats in groups 2-6 were pretreated with 10 mg/kg body weight (b.w.) Cyclophosphamide orally for 27-days to induce immunosuppression. Thereafter, they received treatment orally for 28 days as follows: Group 2 (distilled water), group 3 (5 mg/kg b.w. Levamisole), groups 4-6 (60, 90 and 120 mg/kg b.w. ASEDS, respectively). HPLC was used to determine major compounds in ASEDS. The effects of ASEDS on immune cells, immunoglobulins A, G and M levels, lipoproteins, and antioxidant status of rats were evaluated.

RESULTS

ASEDS indicated high content of Acutumine, Quinine, Catechin, Chlorogenic acid, Gallic acid, Quercetin, Vanillic acid, Luteolin, Formosanin C, Saponin, Cyanidin, Tannic acid, 3-Carene, Limonene and α-terpineol. Cyclophosphamide triggered significant (p < 0.05) reduction in total leucocyte count and differentials, IgA, IgG, high-density lipoproteins (HDL), catalase, superoxide dismutase, glutathione peroxidase, vitamins A, C and E levels of untreated rats. Administration of ASEDS led to significant (p < 0.05) improvement in immune cell counts, immunoglobulin synthesis, high-density lipoprotein concentration, and antioxidant status of rats in the treated groups.

CONCLUSIONS

The results obtained from the study showed the immunomodulatory activity of ASEDS, thereby indicating its potential in immunostimulatory drug discovery.

Quality Evaluation of Market Acacia catechu by Fingerprint-Chemical Pattern Recognition

Acacia catechu (L.f.) Willd, a leguminous plant, is included in the 2020 edition of the Chinese Pharmacopoeia and is mainly used to treat eczema, mouth ulcers, diarrhea, bruising, and traumatic hemorrhage. However, there are imported and domestic Acacia catechu samples available in China, and their quality and price are very different, which seriously affects the safety and stability of their clinical application. Importantly, there is no simple and effective method for identifying or classifying grades of Acacia catechu. In this study, 47 batches of commercial Acacia catechu were used for identifying or classifying grades of Acacia catechu using high performance liquid chromatography (HPLC) combined with chemometric analysis. Firstly, gradient elution was adopted with 0.05% phosphoric acid water (A)-methanol (B) as the mobile phase to establish chromatographic conditions. The HPLC chromatograms of 47 batches of Acacia catechu samples were analyzed by the “Similarity Evaluation System for Chromatographic Fingerprint of TCM” software (version 2012A). The common peaks of Acacia catechu were identified to evaluate the similarity. Based on the determination results of fingerprint chromatographic peak area, the quality of the collected Acacia catechu was evaluated by chemometric methods such as CA, PCA, and OPLS-DA. The results showed that the collected Acacia catechu samples were significantly divided into three categories. The first-class samples were all imported Acacia catechu except S9 sample, which was domestic Acacia catechu; the second-class samples were partly domestic Acacia catechu and partly imported Acacia catechu; and the third-class samples were all domestic Acacia catechu. Moreover, OPLS-DA of 47 batches of samples showed that the contents of catechin and the total contents of catechin and epicatechin could be used as key indicators for assessing the quality of Acacia catechu. The developed HPLC fingerprint and quantitative analysis method of multi-indicator components can be used for classification and quality evaluation of market Acacia catechu, which has a significant reference value for developing Acacia catechu grade quality standards.

Antidiabetic potential of Catechu via assays for α-glucosidase, α-amylase, and glucose uptake in adipocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Catechu is the dry water extract of barked branches or stems from Senegalia catechu(L. F.)P. J. H. Hurter & Mabb, which is used as a hypoglycemic regulator in recent researches. Potential anti-hyperglycemic components and the putative mechanisms were evaluated in this investigation.

AIM OF THE STUDY

Evaluated the hypoglycemic activity of Catechu via α-glucosidase, α-amylase inhibition assays, and glucose uptake in 3T3-L1 adipocytes.

MATERIALS AND METHODS

The effects of Catechu on α-glucosidase, α-amylase inhibition assays and glucose uptake experiment were tested after the ethanol extract of Catechu (EE) was sequentially partitioned with petroleum ether (PEE), ethyl acetate (EAE), and n-butanol fractions (NBE). Next, HPLC-MS and traditional Chinese medicine (TCM) database were used to detect and analyze the primary active ingredients presented in hypoglycemic fraction. In addition, in silico molecular docking study was used to evaluate the candidates' inhibitory activity against α-glucosidase and α-amylase.

RESULTS

The results of α-glucosidase and α-amylase inhibition assays indicated that all fractions, with the exception of PEE, presented significant inhibitory effects on α-glucosidase and α-amylase. The inhibitory effect of NBE on α-glucosidase was similar to the positive control (NBE IC₅₀ = 0.3353 ± 0.1215 μg/mL; Acarbose IC₅₀ = 0.1123 ± 0.0023 μg/mL). Furthermore, the inhibitory kinetics of α-glucosidase revealed that all fractions except for PEE belong to uncompetitive type. In silico molecular docking analysis showed that the main compositions of NBE ((-)-epicatechin, cyanidin, and delphinidin) possessed superior binding capacities with α-glucosidase (3WY1 AutoDock score: 4.82 kcal/mol; -5.59 kcal/mol; -5.63 kcal/mol) and α-amylase (4GQR AutoDock score: 4.80 kcal/mol; -5.89 kcal/mol; -4.26 kcal/mol), respectively. The results of glucose uptake experiment indicated that EE, PEE, EAE, and NBE without significant promotion effect on glucose uptake rate of 3T3-L1 adipocytes (P > 0.05).

CONCLUSION

This study revealed that the hypoglycemic effect of Catechu might be related to the inhibitory effects of phenols on digestive enzymes (α-glucosidase and α-amylase), and the possible active phenols were (-)-epicatechin, cyanidin, delphinidin and their derivatives, which provided scientific evidences for Catechu's traditional use to treat T2DM.

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.

A Comprehensive Review on the Chemical Composition and Pharmacological Activities of Acacia catechu (L.f.) Willd

With the emergence of epidemics, pandemics, and infectious diseases, several research activities have been carried out on natural products to tackle them. As there are structural diversities in natural products, researchers are focused on exploring them for treatment and/or management of various infections and/or diseases. Acacia catechu (L.f.) Willd. belonging to the order Fabales and family Fabaceae shows a wide range of pharmacological functions in the management of diseases in humankind. This review was carried out to gather and provide information about the chemical constituents and pharmacological activities of A. catechu through the literature survey of scientific articles. On preliminary assessments, A. catechu is demonstrated as a significant wellspring of bioactive compounds with a wide range of biological and pharmaceutical applications such as antidiabetic, antioxidant, antimicrobial, anticancer, antidiarrheal, anti-inflammatory, antiviral, hepatoprotective, immunomodulatory, and so on. Although the metabolites from the plant are reported with diverse pharmacological applications, there is little information in regards to toxicity and clinical trials on bioactive compounds of this plant. Further research on diverse bioactive compounds from the plant is required to develop them as a successful potent drug.

Protective effect of (+)-catechin against lipopolysaccharide-induced inflammatory response in RAW 264.7 cells through downregulation of NF-κB and p38 MAPK

Catechin, a flavonol belonging to the flavonoid group of polyphenols is present in many plant foods. The present study was done to evaluate the effect of catechin on various inflammatory mediators using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. The effect of catechin on total cyclooxygenase (COX) activity, 5-lipoxygenase (5-LOX), myeloperoxidase, nitrite and inducible nitric oxide synthase (iNOS) level, secretion of tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) were assessed in LPS-stimulated RAW 264.7 cells. The expression of COX-2, iNOS, TNF-α, nuclear factor-ĸB (NF-κB) and p38 mitogen-activated protein kinase (MAPK) genes were also investigated. The effect was further analyzed using human PBMCs by assessing the level of TNF-α and IL-10. The study demonstrated that the inflammatory mediators such as COX, 5-LOX, nitrite, iNOS, and TNF-α were significantly inhibited by catechin in a concentration-dependent manner whereas IL-10 production was up-regulated in RAW 264.7 cells. Moreover, catechin down-regulated the mRNA level expression of COX-2, iNOS, TNF-α, NF-κB and p38 MAPK. The current study ratifies the beneficial effect of catechin as a dietary component in plant foods to provide protection against inflammatory diseases.

Sequential extraction and enrichment of flavonoids from Euonymus alatus by ultrasonic-assisted polyethylene glycol-based extraction coupled to temperature-induced cloud point extraction

A green method for simultaneous extraction and enrichment of flavonoids from Euonymus alatus was developed by ultrasonic-assisted extraction (UAE) and temperature-induced cloud point extraction (TICPE) using PEG-base aqueous solution as the extractant. Based on screening different molecular weights of PEGs, PEG-400/water was used as the extractant, and the effects of key factors on extraction yields of flavonoids were investigated by single-factor experiments and response surface methodology (RSM). The optimum conditions of UAE were as follows: PEG-400 concentration of 16% (w/w), particle size of 80 mesh, solvent-to-material ratio of 60:1, extraction temperature of 90 °C and extraction time of 15 min. The results obtained by validation experiments were consistent with the values predicted by RSM. Temperature-induced formation of the aqueous two-phase system (ATPS) and TICPE process were further investigated by controlling temperature and adding (NH₄)₂SO₄. In the presence of (NH₄)₂SO₄, the ATPS formed at 75 ℃ and pH 3.5 could effectively improve separation and recovery of flavonoids with enrichment factor of above five times. Gallic acid, catechin, dihydromyricetin and ellagic acid in the extract were identified and confirmed by UPLC-Q-TOF-MS and the corresponding standards. The UAE-TICPE coupled to HPLC was successfully applied for extraction and determination of flavonoids in two batches of Euonymus alatus. The extraction yields of catechin, dihydromyricetin and total flavonoids were 0.377-0.684 mg/g, 1.091-1.353 mg/g and 2.612-3.146 mg/g, respectively. Compared to conventional extraction methods, PEG-based UAE integrated with TICPE in one-step procedure exhibited higher extraction efficiency and better extraction selectivity.

Role of L. plantarum KX519413 as Probiotic and Acacia Gum as Prebiotic in Gastrointestinal Tract Strengthening

Probiotics, prebiotics, and synbiotics are potential mediators to maintaining healthy intestinal flora and have garnered an area of wide research in the past few years. The current study assesses the in vivo effects of probiotic (Lactobacillus plantarum MBTU-HK1), prebiotic (acacia gum) (either singly or in combination as a synbiotic on growth performance), biochemical, hematological, physiological, and immunological effects and their role in the reduction of procarcinogen enzyme activities in male Balb/c mice. The absence of treatment-related toxicity and a normal physiological range of biochemical and hematological parameters ensure their safe consumption. The synbiotic group was found to possess lowered cholesterol levels and enhanced protein and mineral content. The probiotic and synbiotic groups reinforced immunoglobulin levels and had a modulatory effect on phagocytosis. A lymphocyte proliferation pattern suggested the stimulatory effect of synbiotic combination on splenocyte viability and proliferation. Total antioxidant capability in the liver was determined by a 2,2-diphenyl-1-picrylhydrazyl assay and all the treatment groups were found to possess increased scavenging activity. Synbiotic and prebiotic treatment was observed to lead to reduced tumor necrosis factor α (TNF-α) levels. Bacterial procarcinogenic fecal enzyme activities were found to be decreased, proving their role in the prevention of colon cancer incidence. This study proves the potency and safety of oral administration of L. plantarum MBTU-HK1 and acacia gum either individually or in combination.