Toxicological assessment of Opuntia dillenii (Ker Gawl.) Haw. cladode methanol extract, fractions and its alpha pyrones: Opuntiol and opuntioside.

ETHNOPHARMACOLOGICAL RELEVANCE: The edible plant Opuntia dillenii (Ker Gawl.) Haw. commonly known as Nagphana, belongs to the Cactaceae family. It is traditionally used to treat various ailments including inflammation, gastric ulcers, diabetes, hepatitis, asthma, whooping cough and intestinal spasm. AIM OF THE STUDY: Despite its traditional use in various countries, detailed toxicological studies of O. dillenii cladode are few. Thus in the current study, toxicity of O. dillenii cladode derived methanol extract, fractions and its α-pyrones: opuntiol and opuntioside have been addressed. METHODS: The test agents were assessed using both in vitro and in vivo toxicity assays. MTT on human embryonic kidney cell line (HEK-293), tryphan blue exclusion in rat neutrophils, Cytokinesis-B block micronucleus (CBMN) in human lymphocytes and genomic DNA fragmentation using agarose gel electrophoresis were performed. In acute toxicity test, mice orally received extract (5 g/kg) for 7 days followed by measurements of relative organ weight, biochemical (blood profile, liver and kidney function test) and histological studies (liver and kidney) were carried out. Rat bone marrow micronucleus genotoxicity assay was also conducted. RESULTS: O. dillenii derived test agents were non-cytotoxic and had no effect on the integrity of DNA. Methanol extract (5 g/kg) orally administered in mice did not cause any significant change in relative organ weights, biochemical parameters and liver and kidney histology as compared to vehicle control. In parallel, extract did not stimulate micronuclei formation in rat bone marrow polychromatic erythrocytes. CONCLUSION: These results led to conclude that edible O. dillenii extract is non-toxic via the oral route and appears to be non-cyto-, hepato-, nephro- or genotoxic, thereby supporting its safe traditional use against various ailments. Therefore, opuntiol and opuntioside may serve as lead compounds in designing new drug(s) derived from edible plants.

Opuntioside, opuntiol and its metallic nanoparticles attenuate adjuvant-induced arthritis: Novel suppressors of Toll-like receptors -2 and -4.

Rheumatoid arthritis (RA) is a chronic autoimmune disease of synovial inflammation and joint destruction. This study reports anti-arthritic potential of opuntioside-I opuntiol, and its gold and silver nanoparticles (NPs) against Complete Freund's Adjuvant (CFA)-induced arthritic rats. The mechanistic studies were performed targeting TLRs (TLR-2 and TLR-4) and cytokines (IL-1ß and TNF-α) expressions to validate their anti-inflammatory and immuno-modulatory response. The nano-formulations were successfully characterized employing Atomic Force Microscopy (AFM) and Dynamic Light Scattering (DLS) analysis. Opuntiol and opuntioside (OP and OPG: 10, 50 and 100 mg/kg) and opuntiol-coated silver and gold NPs (OP-AgNPs and OP-AuNPs: 0.5, 1 and 3 mg/kg) treatments in arthritic rat have shown minimal arthritic score exhibiting mild to moderate articular changes and tissue swelling in ankle joints. Radiographic examination reveals significant reduction in synovitis with improvement in joints degenarative changes in the presence of aforementioned treatments. Likewise, histology of rat ankle joints depicted comparatively lesser influx of inflammatory cells and diminished granulamatous inflammation. Moreover, treatment groups suppressed protein and mRNA expressions of TLRs (TLR-2 and TLR-4) and cytokines (IL-1ß and TNF-α) levels were also significantly declined in the presence of OPG, OP and its NPs comparing to arthritic control. This investigation concludes, the tested compounds and nano-formulations successfully restored the disease progression in CFA-induced arthritic rat owing to their immunomodulatory and anti-inflammatory potentials and can be considered for RA targeted therapy to address the utmost challenges of the disease.

Opuntia dillenii cladode: Opuntiol and opuntioside attenuated cytokines and eicosanoids mediated inflammation.

ETHANOPHARMACOLOGICAL RELEVANCE: Opuntia dillenii Haw (Nagphana) traditionally used against inflammation. The present study addressed the anti-inflammatory activity of O. dillenii derived methanol extract, fractions and pure compounds and their underlying mechanism of action. MATERIALS AND METHODS: O. dillenii cladode methanol extract was subjected to vacuum liquid chromatography (VLC) furnishing two main fractions viz (T-1 and -2) leading to isolation of opuntiol (aglycone) and opuntioside (O-glucoside), respectively. Anti-inflammatory activity of extract, fractions, pure compounds and reference drugs were evaluated using: (1) arachidonic acid (AA) and 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced ear edema accompanied by histological studies of mice ear sections and phospholipase A2 (PLA2)-induced mice paw edema. (2) Carrageenan and glycogen-induced peritonitis in rodents. In parallel levels of leukotriene B4 (LTB4) and reactive oxygen species (ROS) were also determined via HPLC and fluoroemetrically using 2', 7'-dichlorodihydrofluorescein diacetate (DCFH-DA) dye, respectively. Additionally, levels of prostaglandin E2 (PGE2), tumor necrosis factor (TNF-α), interleukins IL-1ß and -6 were measured by ELISA assay. RESULTS: O. dillenii methanol extract, fractions and pure compounds reduced AA and TPA-induced ear punch weight in a dose dependent fashion. The corresponding IC50 values obtained also suppressed inflammatory features observed histologically. Furthermore, paw edema and peritonitis were also attenuated. Similar to indomethacin and diclofenac sodium, opuntioside reduced PGE2 levels of inflamed ear which was comparatively 1.3× better than opuntiol. However, opuntiol was more potent in reducing LTB4 levels in rat neutrophils with an IC50 value of 19±3.3µΜ, while opuntioside was ineffective. Opuntiol also effectively suppressed ROS (37%) and cytokine levels (TNF-α, IL-1ß and -6) by ~50% and comparable to dexamethasone. CONCLUSIONS: O. dillenii cladodes possess anti-inflammatory properties via inhibition of arachidonic acid metabolites and cytokines. Opuntiol (aglycone) emerged as a dual inhibitor of cyclooxygenase (COX) and lipooxygenase (LOX) pathways. It also suppressed ROS and cytokine levels. However, opuntioside manifested its selectivity towards COX (PGE2) pathway without affecting LTB4 levels. The present report describing the anti-inflammatory activity of opuntiol and opuntioside for the first time thereby, supporting and justifying the traditional use of O. dillenii against inflammation and may serve as lead compound in designing of new anti-inflammatory agents.

Hypotensive activity, toxicology and histopathology of opuntioside-I and methanolic extract of Opuntia dillenii.

Methanolic extract of Opuntia dillenii cladodes and its pure compound alpha-pyrone glycoside, opuntioside-I showed potent hypotensive activity in normotensive rats. Both the extract and opuntioside-I showed comparable effect of 44-54% fall in Mean Arterial Blood Pressure (MABP) at the dose of 10 mg/kg. No mortality was observed in rats even at the doses of 1000 mg/kg/d and 900 mg/kg/d per oral of extract and opuntioside-I respectively. However, histopathology revealed adverse effects of high doses on liver and spleen of the experimental animals.