Effects of n-hexane fraction of Piper guineense seed extract on Nω-nitro-L-arginine methyl ester hydrochloride-induced hypertension in rats.

This study aimed to investigate the effects of the n-hexane fraction of the ethanolic seed extract of PG (NFESEPG) on hypertension induced by Nω-nitro-L-arginine methyl ester (L-NAME) in rats. Specifically, the study examined the impact of NFESEPG on blood pressure, oxidative stress markers, NO concentration, angiotensin-converting enzyme (ACE) and arginase activities, and cardiac biomarkers in hypertensive rats. The study involved collecting, identifying, and processing the PG plant to obtain the ethanolic seed extract. The extract was then partitioned with solvents to isolate the n-hexane fraction. Hypertension was induced in rats by oral administration of L-NAME for 10 days, while concurrent treatment with NFESEPG at two doses (200 and 400 mg/kg/day) was administered orally. Blood pressure was measured using a noninvasive tail-cuff method, and various biochemical parameters were assessed. Treatment with both doses of NFESEPG significantly reduced systolic and diastolic blood pressure in L-NAME-induced hypertensive rats. Additionally, NFESEPG administration increased NO concentration and decreased ACE and arginase activities, malondialdehyde (MDA) levels, and cardiac biomarkers in hypertensive rats. The findings indicate that NFESEPG effectively lowered blood pressure in hypertensive rats induced by L-NAME, potentially through mechanisms involving the modulation of oxidative stress, NO bioavailability, and cardiac biomarkers. These results suggest the therapeutic potential of NFESEPG in managing hypertension and related cardiovascular complications.

Effect of soaking and air-resting on the phytochemical, antioxidant, and antimicrobial properties of Piper guineense (Schum and Thonn) seeds.

BACKGROUND: Soaking and air-resting are processing steps in malting. This has been reported to increase metabolic and enzyme activities in rice paddy as a result of exposure of the grain to atmospheric oxygen. The present study evaluated the effect of soaking and air-resting on the phytochemical composition of Piper guineense seeds. The seed extracts were prepared by: soaking the seeds in water for 4 h; air-resting for 30, 60, 90, and 120 min; and re-soaking for another 4 h. The out-of-steep seeds were milled and an extract was formed by tissue homogenization and maceration using ethanol. The phytochemical, antioxidant, and antibacterial properties of the seed extract were determined using standard methods. RESULTS: The alkaloid, flavonoid, saponin, tannin, and total phenol contents were 0.126-0.268, 0.091-0.172, 0.080-0.123, 0.00-0.107, and 0.447-0.908 g kg-1 respectively. The antioxidant properties (reducing power) of the seed extracts were concentration-dependent and were in the range 1.08-3.24 g kg-1 at 8 mg mL-1 , 1.14-3.47 g kg-1 at 16 mg mL-1 , 1.30-3.35 g kg-1 at 24 mg mL-1 , 1.26-3.11 g kg-1 at 32 mg mL-1 , and 1.13-3.04 g kg-1 at 40 mg mL-1 , respectively. The antibacterial activities against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa showed that, at 100 mg mL-1 , the inhibition zone diameters of the seed extracts were in the range 10-23 mm. CONCLUSION: Soaking and air-resting of P. guineense seeds increased the phytochemical components of the seeds. The extracts from the seeds air-rested for 30 min showed the highest phytochemical contents and had the highest antioxidant and antimicrobial properties. © 2022 Society of Chemical Industry.

The Effects of Piper Guineense versus Sesamum Indicum Aqueous Extracts on Lipid Metabolism and Antioxidants in Hypercholesterolemic Rats.

BACKGROUND: Piper guineense (PG) and Sesamum indicum (SI) have been shown to be rich sources of antioxidants and other health benefits; hence, we evaluated the impact of its consumption in hypercholesterolemic model on lipid metabolism. METHODS: Forty-eight animals were divided into eight groups of six rats each. Rats were given cholesterol (40 mg/0.3ml), PG and SI extract (100 and 200 mg/kg), and Questran (0.26 g/kg) orally, five times a week for 28 days. Lipid profile, hepatic antioxidant status, biomarkers of liver toxicity, and tissue histopathology were examined. Data were analyzed using one-way ANOVA and P<0.05 were considered statistically significant. RESULTS: Cholesterol feeding caused 100% gain in weight, significantly increased AST, LPO (P=0.41 and 0.002) but significantly decreased SOD (P=0.003) compared to control. CHPG(1)/(2) and CHSI(1)/(2) caused a significant decrease (P=0.01, 0.005, 0.003, and 0.023) in cholesterol-induced body-weight gain and decreased serum total cholesterol by 20-30% compared to untreated-hypercholesterolemic rats. Triglyceride and LDL-c decreased with extract administration and specifically HDL-c increased significantly (P<0.001) by CHSI(1) compared to untreated-hypercholesterol rats. Furthermore, an increase in HDL-c was higher (P=0.04 and 0.002) by SI compared to PG at both doses. CONCLUSION: These results indicate that PG and SI exerts a hypolipidemic effect, reduces cholesterol intake induced body weight gain, and increases the body's antioxidant defense system in experimental hypercholesterolemia.

The use of black pepper (Piper guineense) as an ecofriendly antimicrobial agent to fight foodborne microorganisms.

Consumers demand clean-label food products, necessitating the search for new, natural antimicrobials to meet this demand while ensuring food safety. This review aimed at investigating the antimicrobial properties of black pepper (Piper guineense) against foodborne microorganisms. The existence of foodborne illness, food spoilage, food waste, the resulting negative economic impact of these issues, and consumer interests have all pushed the food industry to find alternative, safe, and natural antimicrobials to be used in foods and beverages. Consumers have also influenced the demand for novel antimicrobials due to the perceived association of current synthetic preservatives with diseases and adverse effects on children. They also have a desire for clean-label products. These combined concerns have prompted researchers at investigating plant extracts as potential sources for antimicrobials. Plants possess many antimicrobial properties; therefore, evaluating these plant extracts as a natural source of antimicrobials can lead to a preventative control method in reducing foodborne illness and food spoilage, inclusively meeting consumer needs. In most regions, P. guineense is commonly utilized due to its potent and effective medicinal properties against foodborne microorganisms.

Glycosides of polygalacic acid from the stem barks of Piper guineense Schum and Thonn.

In a continuation of our study on constituents of P. guineense now focusing on the search for saponins, phytochemical investigation of the n-BuOH fraction of P. guineense stem bark led to the isolation of three previously undescribed triterpenoid saponins, named guineenosides A─C (1─3). Their structures were established on the basis of extensive analysis of 1D and 2D NMR (1H, 13C NMR, DEPT, COSY, TOCSY, NOESY, HSQC, HSQC-TOCSY and HMBC) and HRESIMS experiments, and by chemical evidence as 3-O-{α-l-rhamnopyranosyl-(1 â†’ 3)-ß-d-xylopyranosyl-(1 â†’ 2)-α-l-arabinopyranosyl-(1 â†’ 4)-α-l-rhamnopyranosyl-(1 â†’ 3)-[α-l-arabinofuranosyl-(1 â†’ 4)]-α-l-rhamnopyranosyl-(1 â†’ 3)-ß-d-fucopyranosyl} polygalacic acid 28-O-α-l-rhamnopyranosyl-(1 â†’ 4)-α-l-rhamnopyranosyl-(1 â†’ 3)-ß-d-xylopyranosyl ester (1), 3-O-{α-l-rhamnopyranosyl-(1 â†’ 3)-ß-d-xylopyranosyl-(1 â†’ 2)-α-l-arabinopyranosyl-(1 â†’ 4)-α-l-rhamnopyranosyl-(1 â†’ 3)-[α-l-arabinofuranosyl-(1 â†’ 4)]-α-l-rhamnopyranosyl-(1 â†’ 3)-ß-d-fucopyranosyl} polygalacic acid 28-O-ß-d-glucopyranosyl-(1 â†’ 3)-α-l-rhamnopyranosyl-(1 â†’ 4)-α-l-rhamnopyranosyl-(1 â†’ 3)-ß-d-xylopyranosyl ester (2), and 3-O-{α-l-rhamnopyranosyl-(1 â†’ 2)-ß-d-xylopyranosyl-(1 â†’ 3)-ß-d-fucopyranosyl} polygalacic acid 28-O-[α-l-rhamnopyranosyl-(1 â†’ 4)-α-l-rhamnopyranosyl-(1 â†’ 3)-ß-d-xylopyranosyl ester (3). This is the first report of triterpenoid saponins from P. guineense.

Evaluating the potentials of randomised integrated control trial on tungiasis in a South-western Nigerian community.

Considering the fact that new, safe and incorporable treatment alternatives to therapeutic prophylaxis for tungiasis are lacking and sometimes proving difficult, this present study evaluated the potentials of integrating control approach involving focal premise treatment using 5% emulsifiable concentrate of cypermethrin, and topical application of Piper guineense oil with personal protection. Of the 90 houses selected, their floors were classified into paved rooms & unpaved verandas, paved verandas & unpaved rooms, paved rooms & verandas, and unpaved rooms & verandas, and tested for the presence of sand fleas using the sweeping and beating as well as soil collection and extraction by tullgren funnel method before fumigation. A total of 100 individuals partitioned into four groups of 25 individuals each were assigned 3%, 5%, 10% and 15% of P. guineense oil irrespective of stages of embedded fleas. The mean of sand fleas decreased from 1.14, 0.07, 0.21, and 1.66 to 0.37, 0.02, 0.09 and 1.08 after two weeks of single spray compared to the untreated location (p <  0.001). Furthermore, the mean lesions of stage I reduced to 0 after 2 to 6 days of 3%, 5%, 10% and 15% ointment application, and stage II and III after 10 to 12 days of 10% and 15% application respectively. The difference between tungiasis stages and exposure time for P. guineense ointment was highly significant p = 0.007 and p = 0.0002. Notable reduction in severity score of acute and chronic tungiasis was observed thus indicating effectiveness of the topical ointment. Hexanolic oil extracts of P. guineense in 10% and 15% concentration would kill embedded sand flea and ameliorate the sufferings in endemic settings.

Evaluation of the modulatory effects of Piper guineense leaves and seeds on egg albumin-induced inflammation in experimental rat models.

ETHNOPHARMACOLOGICAL RELEVANCE: Inflammation processes are implicated in many degenerative diseases. Piper guineense, a West African spice belonging to the Piperaceae family has been reported to contain anti-inflammatory agents. AIM OF STUDY: This study determined the modulatory effects of methanolic extracts of Piper guineense leaves and seeds on egg albumin-induced inflammation in rats. STUDY DESIGN AND METHODS: Inflammation in the hind paw was induced by injecting 0.1ml egg albumin subcutaneously. Treatments including diclofenac were given orally. Rectal temperature and paw size were monitored hourly for the first 3 h' post-induction of inflammation and then at the 6th and 24th hour. Serum levels of CRP, MDA, LDH and GGT activities were determined at these hours. RESULTS: Results showed that egg albumin-induced inflammation caused a significant (p < 0.05) increase in paw size and rectal temperature. It further showed that treatment with the leaves and seed extracts reversed the effect of inflammation on serum levels of CRP and MDA, and on LDH and GGT activities similar to diclofenac in rats. CONCLUSION: Extracts of the Piper guineense seed and leaves have potentials of being used as an anti-inflammatory agent but further studies need to be done to determine their toxicity and effects on immunological markers of inflammation.

An ethnobotanical survey and antifungal activity of Piper guineense used for the treatment of fungal infections in West-African traditional medicine.

ETHNOBOTANICAL RELEVANCE: Piper guineense occurs commonly in West Africa where it is used for fungal infections instead of the costly and not always accessible conventional antifungals. Fungal, yeast-based diseases are common in West-Africa especially among those living with HIV/AIDS, and thus this study was performed in Imo state, South-Eastern Nigeria, where P. guineense is predominantly used for the treatment of fungal diseases, such as skin rashes, oral thrush and vaginosis. AIM OF STUDY: The scarce number of previous studies on the documentation of the traditional uses of P. guineense extracts for the treatment of fungal infections in Nigeria prompted this survey. The investigation focused on how traditional healers recognize and diagnose fungal infections, how P. guineense is collected, on the various parts used for the treatments, methods of preparations, administrations and treatments. In addition, an in vitro antifungal screening of P. guineense fruit and leaf extracts of various polarities, and piperine and piperlongumine, representing the main constituents in these extracts, were performed. METHODS: A house to house ethnobotanical survey was conducted using questionnaires. Twenty traditional medical practitioners (TMP) and herb sellers from ten villages were interviewed. Four human pathogenic strains of yeast and Cryptococcus neoformans, a yeast-like basidiomycete causing meningitis in immunocompromised individuals, were used for the antifungal screening. RESULTS: The traditional medical practitioners (TMP) and herb sellers explained that the leaves and fruits are the most commonly used plant parts for the treatments. The oral intake of the extracts in locally produced bamboo alcohol (Kai-kai) is the most common method of administration. In accordance with these recorded traditional uses, we found that extracts of P. guineense were growth inhibitory against the fungal strains with MIC values ranging from 39 to 2500 µg/mL. The lowest MIC value of 39 µg/mL was recorded for a methanol fruit extract against Candida albicans, C. glabrata and C. tropicalis. In addition, ethanol and hexane fruit extracts were effective against the growth of C. albicans and C. glabrata, respectively, with a MIC of 78 µg/mL. Piperlongumine and piperine were active against C. albicans with MIC values of 39 and 78 µg/mL respectively. CONCLUSION: P. guineense fruit and leaf extracts, as well as their piperamide alkaloid constituents piperine and piperlongumine, have interesting antifungal properties and could have potential as new antifungal scaffolds. Our results warrant further in-depth investigations to isolate and characterize piperamide alkaloids and other compounds responsible for the antifungal activity in the extracts.

Alkaloid-Rich Crude Extracts, Fractions and Piperamide Alkaloids of Piper guineense Possess Promising Antibacterial Effects.

Piper guineense is a food and medicinal plant commonly used to treat infectious diseases in West-African traditional medicine. In a bid to identify new antibacterial compounds due to bacterial resistance to antibiotics, twelve extracts of P. guineense fruits and leaves, obtained by sequential extraction, as well as the piperine and piperlongumine commercial compounds were evaluated for antibacterial activity against human pathogenic bacteria. HPLC-DAD and UHPLC/Q-TOF MS analysis were conducted to characterize and identify the compounds present in the extracts with promising antibacterial activity. The extracts, with the exception of the hot water decoctions and macerations, contained piperamide alkaloids as their main constituents. Piperine, dihydropiperine, piperylin, dihydropiperylin or piperlonguminine, dihydropiperlonguminine, wisanine, dihydrowisanine and derivatives of piperine and piperidine were identified in a hexane extract of the leaf. In addition, some new piperamide alkaloids were identified, such as a piperine and a piperidine alkaloid derivative and two unknown piperamide alkaloids. To the best of our knowledge, there are no piperamides reported in the literature with similar UVλ absorption maxima and masses. A piperamide alkaloid-rich hexane leaf extract recorded the lowest MIC of 19 µg/mL against Sarcina sp. and gave promising growth inhibitory effects against S. aureus and E. aerogenes as well, inhibiting the growth of both bacteria with a MIC of 78 µg/mL. Moreover, this is the first report of the antibacterial activity of P. guineense extracts against Sarcina sp. and E. aerogenes. Marked growth inhibition was also obtained for chloroform extracts of the leaves and fruits against P. aeruginosa with a MIC value of 78 µg/mL. Piperine and piperlongumine were active against E. aerogenes, S. aureus, E. coli, S. enterica, P. mirabilis and B. cereus with MIC values ranging from 39⁻1250 µg/mL. Notably, the water extracts, which were almost devoid of piperamide alkaloids, were not active against the bacterial strains. Our results demonstrate that P. guineense contains antibacterial alkaloids that could be relevant for the discovery of new natural antibiotics.

Modulatory Effect of Methanol Extract of Piper guineense in CCl4-Induced Hepatotoxicity in Male Rats.

This study seeks to investigate the possible protective role of the methanol extract of Piper guineense seeds against CCl4-induced hepatotoxicity in an animal model. Hepatotoxicity was induced by administering oral doses of CCl4 (1.2 g/kg bw) three times a week for three weeks. Group 1 (Control) and Group 2 (CCl4) were left untreated; Piper guineense (PG; 400 mg/kg bw) was administered to Group 3 (T1) by oral gavage for 14 days prior to the administration of CCl4 and simultaneously with CCl4; PG (400 mg/kg bw) was administered simultaneously with CCl4 in Group 4 (T2); and Livolin forte (20 mg/kg bw) was administered simultaneously with CCl4 in Group 5 (T3), the standard drug group. The administration of CCl4 induces histopathological alteration in the liver, with concomitant increased activities of serum hepatic marker enzymes associated with increased levels of lipid peroxidation. Similarly, there was decrease in non-enzymatic (reduced glutathione) and enzymatic antioxidants (glutathione S-transferase), superoxide dismutase, and catalase. An elevation in serum triglyceride and total cholesterol levels was noticed along with decreased levels of serum total protein. Treatment with PG 400 mg/kg bw exhibited excellent modulatory activity with respect to the different parameters studied by reversing all the above-mentioned biochemical changes significantly in the experimental animals. These results suggest that PG offered protection comparable to that of Livolin forte with better efficacy when pre-treated with 400 mg/kg bw 14 days prior to CCl4-exposure.