In vitro antidiabetic potentials, antioxidant activities and phytochemical profile of african black pepper (Piper guineense)

Pipersarmenoids, new amide alkaloids from Piper sarmentosum

A chemical investigation of the aerial parts of Piper sarmentosum resulted in the isolation and identification of 14 amide alkaloids, including three new amide alkaloids, pipersarmenoids A - C (1-3), three new natural amide alkaloids, pipersarmenoids D - F (4-6), and 8 known analogues, N-p-coumaroyltyramine (7), piperlotine C (8), piperlotine D (9), pellitorine (10), sarmentine (11), aurantiamide acetate (12), 1-cinnamoyl pyrrolidine (13) and sarmentamide B (14). Their structures were determined by spectroscopic analysis including HRESIMS and 1D and 2D NMR. The cytotoxicity, neuroinflammation-inhibiting and acetylcholinesterase (AChE) inhibitory activities of those compounds were tested. Compounds 1, 2 and 12 inhibited NO production induced by LPS in BV2 cells with IC50 values of 9.36, 12.53 and 10.77 μM, respectively. Moreover, 1, 2, 7 and 11 showed moderate inhibitory activity on AChE with IC50 values ranging from 37.56 to 48.84 μM.

GC-MS fingerprinting, nutritional composition, in vitro pharmacological activities and molecular docking studies of Piper chaba from Uttarakhand region

This study aimed to evaluate the potential therapeutic effects of Piper chaba (PC) growing in the northern region of India, having differences in the phytochemicals, nutritional content, antimicrobial and antioxidant properties by reducing power assay (RPA), 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, phosphomolybdate assay, and antidiabetic potential by α-amylase assay with change in the geographical location. Outcomes of the gas chromatography-mass spectrometry (GC-MS) analysis revealed that phytochemicals such as piperine (46.69%), kusunokinin (8.9%), and sitostenone (7.57%) are the prominent compounds found in PC. The plant has also shown a good nutritional value, i.e., iron (11.25 mg), calcium (147 mg), and vitamin C (9.30 mg) per 100 g. PC has a higher phenolic content than other species (⁓ 13.75 g/100 g plant powder). Among the four tested bacterial strains, the extract is best responsive toward Escherichia coli (35 ± 0.68 mm) which is more than the standard ciprofloxacin (24 ± 0.8 mm). Similarly, among two tested fungal strains, Saccharomyces cerevisiae shows the best zone of inhibition (ZOI) (27.5 ± 0.8 mm), which is greater than tat of standard amphotericin (20.25 ± 0.28 mm). The DDPH method demonstrated the highest antioxidant activity (⁓ 42.61 ± 1.82 µg/ml). IC50 for the antidiabetic potential of PC was found to be 23.09 ± 0.3 µg/ml against α-amylase assay. A molecular docking study revealed that three compounds, piperine, sitostenone and kusunokinin, showed strong binding affinity toward bacterial tyrosyl-tRNA synthetases, fungal dihydrofolate reductase, and α-amylase, respectively. Therefore, the findings of the current study indicate that PC can be considered as a source of food and medicines, either in the form of traditional preparations or as pure active constituents.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-03996-7.

LC-MS/MS, GC-MS and molecular docking analysis for phytochemical fingerprint and bioactivity of Beta vulgaris L

The plants that we consume in our daily diet and use as a risk preventer against many diseases have many biological and pharmacological activities. In this study, the phytochemical fingerprint and biological activities of Beta vulgaris L. leaf extract, which are widely consumed in the Black Sea region, were investigated. The leaf parts of the plant were dried in an oven at 35 °C and then ground into powder. The main constituents in B. vulgaris were identified by LC-MS/MS and GC-MS analyses. Phenolic content, betaxanthin and betacyanin levels were investigated in the extracts obtained using three different solvents. The biological activity of the extract was investigated by anti-microbial, anti-mutagenic, anti-proliferative and anti-diabetic activity tests. Anti-diabetic activity was investigated by in vitro enzyme inhibition and in-silico molecular docking was performed to confirm this activity. In the LC-MS analysis of B. vulgaris extract, a major proportion of p_coumaric acid, vannilin, protecatechuic aldehyde and sesamol were detected, while the major essential oils determined by GC-MS analysis were hexahydrofarnesyl acetone and phytol. Among the solvents used, the highest extraction efficiency of 2.4% was obtained in methanol extraction, and 36.2 mg of GAE/g phenolic substance, 5.1 mg/L betacyanin and 4.05 mg/L betaxanthin were determined in the methanol extract. Beta vulgaris, which exhibited broad-spectrum anti-microbial activity by forming a zone of inhibition against all tested bacteria, exhibited anti-mutagenic activity in the range of 35.9-61.8% against various chromosomal abnormalities. Beta vulgaris extract, which did not exhibit mutagenic, sub-lethal or lethal effects, exhibited anti-proliferative activity by reducing proliferation in Allium root tip cells by 21.7%. 50 mg/mL B. vulgaris extract caused 58.9% and 55.9% inhibition of α-amylase and α-glucosidase activity, respectively. The interactions of coumaric acid, vanniline, hexahydrofarnesyl acetone and phytol, which are major compounds in phytochemical content, with α-amylase and α-glucosidase were investigated by in silico molecular docking and interactions between molecules via various amino acids were determined. Binding energies between the tested compounds and α-amylase were obtained in the range of - 4.3 kcal/mol and - 6.1 kcal/mol, while for α-glucosidase it was obtained in the range of - 3.7 kcal/mol and - 5.7 kcal/mol. The biological activities of B. vulgaris are closely related to the active compounds it contains, and therefore studies investigating the phytochemical contents of plants are very important. Safe and non-toxic plant extracts can help reduce the risk of various diseases, such as diabetes, and serve as an alternative or complement to current pharmaceutical practices.

Evaluation of the Antidiabetic Activities of the Fruit of Parquetina nigrescens (Afzel.) Bullock and In Silico Identification of Its Antidiabetic Agent

The study investigated the antidiabetic potentials of the fruit extract of Parquetina nigrescens with the aim of justifying its folkloric antidiabetic usage in some part of Nigeria. Acute toxicity test of the plant extract was assessed using Lorke's method. Its antidiabetic activities were assayed in α-amylase, α-glucosidase, glucose, and streptozotocin-induced diabetic rats' models at various doses with acarbose and glibenclamide (5 mg/kg) as positive controls. Molecular docking studies were performed to identify the antidiabetic constituent of the extract and elucidate its possible mechanism of action. The estimated median lethal dose (LD50) of the extract was above 5000 mg/kg. In the α-amylase, α-glucosidase study, the extract elicited concentration-dependent activity similar to acarbose. In the glucose-induced hyperglycaemic model, 200 mg/kg of the extract was the most effective dose with comparable (P > .05) antihyperglycaemic activity to glibenclamide (5 mg kg) at 1 to 4 h. Also in the streptozotocin-induced diabetic rats model, 100 and 200 mg/kg of the extract gave comparable (P > 0.05) activity on days 4 to 14 that were significantly better than that of glibenclamide on days 4 to 7. The n-hexane and ethylacetate fractions of the extract, both at 200 mg/kg were the most active with comparable activity to glibenclamide at all time points. The molecular docking studies identified isorhoifolin as the best binder against alpha amylase with binding energy (-9.1 kcal/mol), alpha glucosidase (-9.4 kcal/mol), sodium-glucose cotransporter-2 (-9.5 kcal/mol), peroxisome proliferator activated receptor gamma (-10.3 kcal/mol), 11β-Hydroxysteroid dehydrogenase (-10.8 kcal/mol), and dipeptidyl peptidase IV (-9.4 kcal/mol). The results of the antidiabetic study of P nigrescence fruit extract justified its usage in ethnomedicne in diabetes management.

Nutritional Profile, GC-MS Analysis and In-silico Anti-diabetic Phytocompounds Candidature of Jatropha gossypifolia Leaf Extracts

BACKGROUND

Diabetes mellitus (DM) is a metabolic disorder known to impair many physiological functions via reactive oxygen species (ROS). Aldose reductase, sorbitol dehydrogenase, dipeptidyl peptidase IV, α-amylase and α-glucosidase are pharmacotherapeutic protein targets in type-2 diabetes mellitus (T2DM). Inhibitors of these enzymes constitute a new class of drugs used in the management and treatment of T2DM. Some reports have claimed that medicinal plant extracts that serves as food (and as an antioxidant source) can reduce these alterations by eliminating ROS caused by DM. Ethnobotanical survey claims Jatropha gossypifolia commonly called "fignut" and "Lapa-lapa" in the Yoruba land of South-western Nigeria, to be used for the treatment and management of diabetes, in addition to its nutritive value.

OBJECTIVE

The nutritional composition and in-silico antidiabetic potential of the bioactive constituents of J. gossypifolia leaf extracts were investigated.

METHODS

Proximate, minerals and gas chromatography-mass spectroscopy (GC-MS) analysis were carried out using standard procedures. Phytocompounds present in J. gossypifolia methanol (JGM) and ethyl acetate (JGE) leaf extracts were tested as potential antagonists of selected protein targets via in-silico techniques. Drug-likeness, pharmacokinetic properties and toxicity of the promising docked ligands were also predicted.

RESULTS

The proximate and mineral analysis revealed good nutritional composition and mineral content. Additionally, cyclo-pentadecane and dibutyl phthalate from methanol extract, and benzene- 1,2,4,5-tetramethyl, benzene-1,2,3,5-tetramethyl, and benzene-1,3-dimethyl-5-(1-methylethyl) from ethyl acetate extract were present in J. gossypifolia leaf which exhibited a better binding affinity than the clinically prescribed standard, metformin.

CONCLUSION

Benzene-1,2,4,5-tetramethyl from JGE extracts exhibited the most promising antidiabetic potential in-silico, suggesting its candidature as diabetes-target-protein inhibitor which may be developed for the treatment of type-2 diabetes mellitus.

Phytosome Supplements for Delivering Gymnema inodorum Phytonutrients to Prevent Inflammation in Macrophages and Insulin Resistance in Adipocytes

Gymnema inodorum (GI) is a leafy green vegetable found in the northern region of Thailand. A GI leaf extract has been developed as a dietary supplement for metabolic diabetic control. However, the active compounds in the GI leaf extract are relatively nonpolar. This study aimed to develop phytosome formulations of the GI extract to improve the efficiencies of their phytonutrients in terms of anti-inflammatory and anti-insulin-resistant activities in macrophages and adipocytes, respectively. Our results showed that the phytosomes assisted the GI extract's dispersion in an aqueous solution. The GI phytocompounds were assembled into a phospholipid bilayer membrane as spherical nanoparticles about 160-180 nm in diameter. The structure of the phytosomes allowed phenolic acids, flavonoids and triterpene derivatives to be embedded in the phospholipid membrane. The existence of GI phytochemicals in phytosomes significantly changed the particle's surface charge from neutral to negative within the range of -35 mV to -45 mV. The phytosome delivery system significantly exhibited the anti-inflammatory activity of the GI extract, indicated by the lower production of nitric oxide from inflamed macrophages compared to the non-encapsulated extract. However, the phospholipid component of phytosomes slightly interfered with the anti-insulin-resistant effects of the GI extract by decreasing the glucose uptake activity and increasing the lipid degradation of adipocytes. Altogether, the nano-phytosome is a potent carrier for transporting GI phytochemicals to prevent an early stage of T2DM.

Antibacterial, antibiofilm, and antimotility signatures of some natural antimicrobials against Vibrio cholerae

Vibrio cholerae is an etiological cause of cholera and has been implicated in several epidemics. Exploration of the antimicrobial signatures of culinary spices has become an important industrial tool to suppress the growth of foodborne bacterial pathogens including Vibrio spp. The antibiofilm and antimotility activities of some selected natural antimicrobial agents were then evaluated. All the extracts showed vibriostatic activities with minimum inhibitory concentration (MIC) ranging from 0.1% to 0.4%. Cinnamon and black pepper demonstrated significant biofilm inhibition activity from 94.77% to 99.77% when administered at 100% MIC. Black pepper extract also demonstrated the highest biofilm inhibition activity against the established biofilms of V. cholerae O1 and O139. Cinnamon, calabash nutmeg, and black pepper significantly inhibited swimming and swarming motility by 85.51% to 94.87%. Sub-MICs (50% and 75%) of some extracts were also effective as an antibiofilm and antimotility agent against the tested strains. The findings of our study suggest the potential application of natural antimicrobial agents such as spices in food to inhibit biofilm formation and motility, which consequently mitigate the virulence and persistence of the pathogen in the food supply chain.

New Carbonic Anhydrase-II Inhibitors from Marine Macro Brown Alga Dictyopteris hoytii Supported by In Silico Studies

In continuation of phytochemical investigations of the methanolic extract of Dictyopteris hoytii, we have obtained twelve compounds (1-12) through column chromatography. Herein, three compounds, namely, dimethyl 2-bromoterepthalate (3), dimethyl 2,6-dibromoterepthalate (4), and (E)-3-(4-(dimethoxymethyl)phenyl) acrylic acid (5) are isolated for the first time as a natural product, while the rest of the compounds (1, 2, 6-12) are known and isolated for the first time from this source. The structures of the isolated compounds were elucidated by advanced spectroscopic 1D and 2D NMR techniques including 1H, 13C, DEPT, HSQC, HMBC, COSY, NEOSY, and HR-MS and comparison with the reported literature. Furthermore, eight compounds (13-20) previously isolated by our group from the same source along with the currently isolated compounds (1-12) were screened against the CA-II enzyme. All compounds, except 6, 8, 14, and 17, were evaluated for in vitro bovine carbonic anhydrase-II (CA-II) inhibitory activity. Eventually, eleven compounds (1, 4, 5, 7, 9, 10, 12, 13, 15, 18, and 19) exhibited significant inhibitory activity against CA-II with IC50 values ranging from 13.4 to 71.6 μM. Additionally, the active molecules were subjected to molecular docking studies to predict the binding behavior of those compounds. It was observed that the compounds exhibit the inhibitory potential by specifically interacting with the ZN ion present in the active site of CA-II. In addition to ZN ion, two residues (His94 and Thr199) play an important role in binding with the compounds that possess a carboxylate group in their structure.

The potential role of Piper guineense (black pepper) in managing geriatric brain aging: a review

Brain aging is one of the unavoidable aspects of geriatric life. As one ages, changes such as the shrinking of certain parts (particularly the frontal cortex, which is vital to learning and other complex mental activities) of the brain may occur. Consequently, communications between neurons are less effective, and blood flow to the brain could also decrease. Efforts made at the biological level for repair become inadequate, leading to the accumulation of β-amyloid peptide in the brain faster than its probable degradation mechanism, resulting in cognitive malfunction. Subsequent clinical usage of drugs in battling related brain-aging ailments has been associated with several undesirable side effects. However, recent research has investigated the potential use of natural compounds from food in combating such occurrences. This review provides information about the use of Piper guineense (black pepper) as a possible agent in managing brain aging because of its implications for practical brain function. P. guineense contains an alkaloid (piperine) reported to be an antioxidant, anti-depressant, and central nervous system stimulant. This alkaloid and other related compounds are neuroprotective agents that reduce lipid oxidation and inhibit tangles in the brain tissues.

Root extracts of Anacardium occidentale reduce hyperglycemia and oxidative stress in vitro

Background

Hyperglycemia is the hallmark of diabetes, and the associated oxidative stress is a major concern that invites an array of diabetic complications. The traditional practices of medicare are of great, current interest due to the high cost and side effects of conventional diabetic medications. The present in vitro study focuses on evaluating the potential of various A. occidentale root extracts for their antihyperglycemic and antioxidant potentials.

Materials and methods

The four different solvent extracts petroleum ether (PEAO), chloroform (CHAO), ethyl acetate (EAAO), and 80 % methanol (80 % MAO) of A. occidentale roots were evaluated for their total phenolic, flavonoid, and antioxidant capacity. Using MIN6 pancreatic β-cells, the cytotoxicity of the extracts was evaluated by MTT assay and the antidiabetic potential by quantifying the insulin levels by ELISA at a higher concentration of glucose. The effect of 80 % MAO on INS gene expression was determined by qRT PCR analysis.

Results

Among the four different solvent extracts of A. occidentale roots, 80 % MAO showed the highest concentration of phenolics (437.33 ± 0.03 µg GAE/mg), CHAO to be a rich source of flavonoids (46.04 ± 0.1 µg QE/mg) and with the highest total antioxidant capacity (1865.33 ± 0.09 µg AAE/ mg). Evaluation of the free radical scavenging and reducing properties of the extracts indicated 80 % MAO to exhibit the highest activity. The MTT assay revealed the least cytotoxicity of all four extracts. 80 % MAO enhanced INS up-regulation as well as insulin secretion even under high glucose concentration (27mM).

Conclusions

The present study demonstrated that the A. occidentale root extracts have effective antihyperglycemic and antioxidative properties, together with the potential of normalizing the insulin secretory system of β-cells. Above mentioned properties have to be studied further by identifying the active principles of A. occidentale root extracts and in vivo effects. The prospect of the present study is identifying drug leads for better management of diabetes from the A. occidentale root extracts.

Graphical abstract