The leaves of Bougainvillea spectabilis suppressed inflammation and nociception in vivo through the modulation of glutamatergic, cGMP, and ATP-sensitive K+ channel pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Bougainvillea spectabilis is an ornamental shrub from Nyctaginaceae family, widely used in the traditional medicine in the treatment of pain, inflammation, and ulcer. Some research investigated the analgesic potential of this plant, however, the in-depth analysis of its antinociceptive properties and molecular mechanism(s) are yet to be revealed.

PURPOSE OF THE STUDY

This study, therefore, investigated the antinociceptive potential of methanol extract of the leaves of B. spectabilis (MEBS) with possible molecular mechanism(s) of action using several pre-clinical models of acute and chronic pain in mice.

MATERIALS AND METHODS

The dry leaf powder of B. spectabilis was macerated with 100% methanol, and then dried crude extract was used for in vivo experiments. Following the acute toxicity test with 500, 1000, and 2000 mg/kg b.w. doses of MEBS, the central antinociceptive activities of the extract (50, 100, and 200 mg/kg b.w.) were evaluated using hot plate and tail immersion tests, whereas the peripheral activities were investigated using acetic acid-induced writhing, formalin-induced licking and oedema, and glutamate-induced licking tests. Moreover, the possible involvements of cGMP and ATP-sensitive K+ channel pathways in the observed antinociceptive activities were also investigated using methylene blue (20 mg/kg b.w.) and glibenclamide (10 mg/kg b.w.), respectively. We also performed GC/MS-MS analysis of MEBS to identify the phyto-constituents and in silico modelling of the major compounds for potential molecular targets.

RESULTS

Our results demonstrated that MEBS at 50, 100, and 200 mg/kg b.w. doses were not effective enough to suppress centrally mediated pain in the hot plate and tail immersion models. However, the extract was potent (at 100 and 200 mg/kg b.w. doses) in reducing peripheral nociception in the acetic acid-induced writhing and inflammatory phase of the formalin tests. Further analyses revealed that MEBS could interfere with glutamatergic system, cGMP and ATP-sensitive K⁺ channel pathways to show its antinociceptive properties. GC/MS-MS analysis revealed 35 different phytochemicals with potent anti-inflammatory and antinociceptive properties including phytol, neophytadiene, 2,4-Di-tert-butylphenol, fucoxanthin, and Vit-E. Prediction analysis showed high intestinal absorptivity and low toxicity profiles of these compounds with capability to interact with glutamatergic system, inhibit JAK/STAT pathway, scavenge nitric oxide and oxygen radicals, and inhibit expression of COX3, tumor necrosis factor, and histamine.

CONCLUSION

Taken together, these results suggested the antinociceptive potentials of MEBS which were mediated through the modulation of glutamatergic, cGMP, and ATP-sensitive K⁺ channel pathways. These also suggested that MEBS could be beneficial in the treatment of complications associated with nociceptive pain.

Evaluation of anti-nociceptive and anti-inflammatory activities of the methanol extract of Holigarna caustica (Dennst.) Oken leaves

ETHNOPHARMACOLOGICAL RELEVANCE

Holigarna caustica (Dennst.) is commonly used in traditional medicine to treat a variety of painful conditions such as eye irritation, inflammation, arthritis, skin diseases, cuts and wounds.

AIM OF THE STUDY

The present study was undertaken to investigate the anti-nociceptive and anti-inflammatory activities of the methanol extract of H. caustica leaves and to elucidate its possible mechanism(s) of action.

MATERIALS AND METHODS

Fresh leaves of H. caustica were collected, dried, and extracted with methanol (MEHC). MEHC was subjected to activity testing, using chemical-induced (acetic acid and formalin test) and heat-induced (hot plate and tail immersion test) pain models. To determine the possible mechanism behind the anti-nociceptive activity of MEHC, the opioid antagonist naltrexone was used to evaluate the involvement of opioid receptors in the case of formalin, hot plate and tail immersion tests, while the involvement of the cGMP and ATP-sensitive K⁺ channel pathways were assessed using methylene blue and glibenclamide respectively, in the acetic acid-induced writhing test. In parallel, the carrageenan-induced paw oedema model was used to determine the anti-inflammatory potential of the extract. Exploratory and motor behaviours were evaluated by the open-field test. Various bioactive compounds potentially responsible for the anti-nociceptive and anti-inflammatory activities were ascertained using GC-MS analysis.

RESULTS

MEHC showed strong, significant and dose-dependent anti-nociceptive activity in all chemical-induced and heat-induced pain models at all experimental doses. The association of opioid receptors with the observed anti-nociceptive effects was confirmed by using naltrexone. The cGMP and ATP-sensitive K⁺ channel pathway was also shown to be involved in the anti-nociceptive activity of MEHC. In addition, MEHC exhibited a dose-dependent inhibition of inflammatory oedema induced by carrageenan. MEHC was not connected with changes in either the locomotor activity or motor responses of mice. In a GC-MS analysis, 40 compounds were identified, among which twelve are documented bioactive compounds with potent analgesic and anti-inflammatory properties.

CONCLUSIONS

Our current study revealed that MEHC possesses strong central and peripheral anti-nociceptive as well as anti-inflammatory activity. It may also be concluded that both opioid receptors as well as the cGMP and ATP-sensitive K⁺ channel pathway are involved in the anti-nociceptive mechanism of MEHC. This study rationalizes the ethnomedicinal use of H. caustica leaves in various painful conditions.

Monitoring of minor compounds in corn oil oxidation by direct immersion-solid phase microextraction-gas chromatography/mass spectrometry. New oil oxidation markers

The aim of this study is to shed light on the evolution of the minor compounds in the corn oil oxidation process, through the information provided by direct immersion-microextraction in solid phase followed by gas chromatography/mass spectrometry (DI-SPME-GC/MS). This methodology enables one, in a single run, to establish the identity and abundance both of original oil minor components, some with antioxidant capacity, and of other compounds coming from both main and minor oil components oxidation. For the first time, some of the compounds formed from oil minor components degradation are proposed as new markers of oil incipient oxidation. Although the study refers to corn oil, the methodology can be applied to any other edible oil and constitutes a new approach to characterizing the oxidation state of edible oils.

Simultaneous determination of tocols, γ-oryzanols, phytosterols, squalene, cholecalciferol and phylloquinone in rice bran and vegetable oil samples

In this study, a simultaneous analytical method of tocols, γ-oryzanols, phytosterols, squalene, cholecalciferol and phylloquinone were developed using HPLC-DAD-FLD. The developed method allowed the quantification of 18 compounds in 30 min. Method validation showed linearity of calibration curves (α = 0.05). RSD of intra-day, inter-day and inter-laboratory precision were less than 4.88%. The limit of detections (LODs) and limit of quantifications (LOQs) were low (0.009-2.166 μg g^-1) with recoveries around 96.0-102.9%. Results derived from the established method demonstrated a wide variation of detected compounds in rice bran and vegetable oil samples (22.4-1774.6 μg g^-1 tocols, ND-26484 μg g^-1 γ-oryzanols, ND-12655 μg g^-1 phytosterols, ND-3189 μg g^-1 squalene, ND-105.3 μg g^-1 cholecalciferol, and ND-54.4 μg g^-1 phylloquinone). Thus, the developed HPLC-DAD-FLD method is a powerful analytical tool for the above mentioned compounds useful in food and pharmaceutical application.

Acacia nilotica leaf improves insulin resistance and hyperglycemia associated acute hepatic injury and nephrotoxicity by improving systemic antioxidant status in diabetic mice

ETHNOPHARMACOLOGICAL RELEVANCE

Acacia nilotica (L.) Delile is used as a traditional anti-diabetic remedy in Bangladesh, Pakistan, Egypt, Nigeria and is mentioned in Ayurveda as well.

AIM

The objective of the study was to evaluate the ethnomedicinal claim of A. nilotica leaf (ANL) extract for its efficiency in ameliorating diabetic complications.

MATERIALS AND METHODS

ANL was orally administrated (50 and 200mg/kg) to alloxanized mice (blood glucose > 200mg/dL) for 20d. Parameters of glucose metabolism, hepatotoxicity, hyperlipidemia and nephrotoxicity were measured with emphasis on elevated oxidative stress. ANL was chemically characterized using GC-MS. Further, docking studies were employed to predict molecular interactions.

RESULTS

ANL lowered (65%, P< 0.001) systemic glucose load in diabetic mice, which was otherwise 398% higher than control. ANL lowered (35%) insulin resistance, without any significant effect on insulin sensitivity (P> 0.05). Anti-hyperglycemic properties of ANL was further supported by lowering of HbA1c (34%; P< 0.001) and improved glucose utilization (OGTT). Overall diabetic complications were mitigated as reflected by lowered hepatic (ALT, AST) and renal (creatinine, BUN) injury markers and normalization of dyslipidemia. Elevated systemic oxidative stress was lowered by increased catalase and peroxidase activities in liver, kidney and skeletal muscle, resulting in 32% decrease of serum MDA levels. Apart from high phenolic and flavonoid content, tocopherol, catechol and β-sitosterol, identified in ANL, demonstrated substantial binding affinity with Nrf2 protein (5FNQ) reflecting possible crosstalk with intracellular antioxidant defense pathways.

CONCLUSION

The present study revealed the potentials of A. nilotica to alleviate diabetes-related systemic complications by limiting oxidative stress which justified the ethnopharmacological antidiabetic claim.

Assessment of anti-diabetic activity of an ethnopharmacological plant Nerium oleander through alloxan induced diabetes in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Nerium oleander L. (syn. Nerium indicum Mill. and Nerium odorum Aiton.) is used for its anti-diabetic properties in Pakistan, Algeria, Morocco and is also recognized in Ayurveda. The present study was undertaken to investigate the anti-diabetic capacity of a standardized hydromethanolic extract of Nerium oleander in alloxan induced diabetes in mice.

MATERIALS AND METHODS

Nerium oleander leaf extract (NOLE) was orally administered at 50 and 200mg/kg body weight (BW) dose to alloxanized mice (blood glucose >200mg/dl). After 20 consecutive days of treatment, various diabetic parameters were studied and compared with untreated mice. Furthermore, gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC) analysis was employed to reveal the phytochemical composition of the plant extract.

RESULTS

NOLE demonstrated antihyperglycaemic activity by reducing 73.79% blood glucose level after 20 days of treatment. Oral glucose tolerance test (OGTT) revealed increase in glucose tolerance as evident by 65.72% decrease in blood glucose in 3h post treatment. Percentage decrease in different liver marker enzymes were significant along with decrease in triglyceride and cholesterol levels, displaying potent antihyperlipidemic activity. Peroxidase and catalase activity in liver, kidney and skeletal muscle were significantly restored besides marked reduction in lipid peroxidation and normalization of hepatic glycogen level in the NOLE treated alloxanized mice. Different bioactive phytocompounds with potent anti-diabetic activity were identified by GC-MS and HPLC analysis.

CONCLUSION

The present investigation revealed that Nerium oleander possess potent anti-diabetic activity as claimed in different ethnopharmacological practices.

Isolation of antioxidant phytoconstituents from the seeds of Lens culinaris Medik

Lens culinaris Medik (Leguminosae) is an annual, bushy and herbaceous plant cultivated globally for its edible seeds. A methanolic extract of the seeds contained four new antioxidant compounds, namely β-sitosteryl-3-(2'-n-eicosanyloxy)-benzoate (3), n-octadec-9-enoyl-1-β-D-glucurano-pyranoside (4) α-D-galactopyranosyl-(6 → 1')-α-D-galactopyranosyl-(6' → 1″)-α-D-galactopyranosyl-(6″ → 1‴)-α-d-galactopyranoside (5) and benzoyl-O-α-D-glucopyranosyl-(2a → 1b)-O-α-D-glucopyranosyl-(2b → 1c)-O-α-D-glucopyranosyl-(6c → 1d)-O-α-D-glucopyranosyl-(6d → 1e)-O-α-D-gluco-pyranoside (6) along with two known compounds n-heptadecanyl n-octadec-9-enoate (1) and β-sitosterol (2) on the basis of chromatographic and spectral data analytical techniques. Compound 3 showed significant antioxidant activity compared to compounds 4, 5, and 6.