In vitro antioxidant and free-radical scavenging activities of polar leaf extracts of Vernonia amygdalina

Neuroprotective potential of traditionally used medicinal plants of Manipur against rotenone-induced neurotoxicity in SH-SY5Y neuroblastoma cells

ETHNOPHARMACOLOGICAL RELEVANCE

Alternanthera sessilis (L.) R. Br. ex DC., Eryngium foetidum L., and Stephania japonica (Thunb.) Miers plants are traditionally used to treat various central nervous system disorders like paralysis, epilepsy, seizure, convulsion, chronic pain, headache, sleep disturbances, sprain, and mental disorders. However, their possible neuroprotective effects have not been evaluated experimentally so far.

AIM OF THE STUDY

The study aims to examine the neuroprotective potential of the three plants against cytotoxicity induced by rotenone in SH-SY5Y neuroblastoma cells and assess its plausible mechanisms of neuroprotection.

MATERIALS AND METHODS

The antioxidant properties of the plant extracts were determined chemically by DPPH and ABTS assay methods. The cytotoxicity of rotenone and the cytoprotective activities of the extracts were evaluated using MTT assays. Microtubule-associated protein 2 (MAP2) expression studies in cells were performed to assess neuronal survival after rotenone and extract treatments. Mitochondrial membrane potential and intracellular levels of reactive oxygen species were evaluated using Rhodamine 123 and DCF-DA dye, respectively. Catalase, glutathione peroxidase, and superoxide dismutase activities were also measured. Apoptotic nuclei were examined using DAPI staining. Liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (LC-QTOF-MS) analysis of the plant extracts was also performed.

RESULTS

The methanol extracts of A. sessilis, S. japonica, and E. foetidum showed excellent free radical scavenging activities. MAP2 expression studies show that A. sessilis and S. japonica have higher neuroprotective effects against rotenone-induced neurotoxicity in SH-SY5Y cells than E. foetidum. Pre-treating cells with the plant extracts reverses the rotenone-induced increase in intracellular ROS. The plant extracts could also restore the reduced mitochondrial membrane potential induced by rotenone treatment and reinstate rotenone-induced increases in catalase, glutathione peroxidase, and superoxide dismutase activities. All the extracts inhibited rotenone-induced changes in nuclear morphology and DNA condensation, an early event of cellular apoptosis. LC-QTOF-MS analysis of the plant extracts shows the presence of neuroprotective compounds.

CONCLUSIONS

The plant extracts showed neuroprotective activities against rotenone-treated SH-SY5Y cells through antioxidant and anti-apoptotic mechanisms. These findings support the ethnopharmacological uses of these plants in treating neurological disorders. They probably are a good source of neuroprotective compounds that could be further explored to develop treatment strategies for neurodegenerative diseases like Parkinson's disease.

Enhancement of skin localization of β-carotene from red fruit (Pandanus conoideus Lam.) using solid dispersion-thermoresponsive gel delivered via polymeric solid microneedles

Red fruit (Pandanus conoideus Lam.) boasts high β-carotene (BC) content, often consumed orally. However, absorption issues and low bioavailability due to food matrix interaction have led to transdermal delivery exploration. Nevertheless, BC has a short skin retention time. To address these limitations, this study formulates a β-carotene solid dispersion (SD-BC) loaded thermoresponsive gel combined with polymeric solid microneedles (PSM) to enhance in vivo skin bioavailability. Characterization of SD-BC includes saturation solubility, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and in vitro release. Characterization of SD-BC thermoresponsive gel includes gelation temperature, viscosity, rheological behaviour, pH, bio-adhesiveness, spreadability, and extrudability. PSM's mechanical properties and insertion capability were assessed. Ex vivo and in vivo dermato-pharmacokinetic studies, drug content, hemolysis, and skin irritation assessments were conducted to evaluate overall performance. Results confirm amorphous SD-BC formation, enhancing solubility. Both SD-BC thermoresponsive gel and PSM exhibit favourable characteristics, including rheological properties and mechanical strength. In vitro release studies showed a seven-fold increase in BC release compared to plain hydrogel. SD-BC thermoresponsive gel combined with PSM achieves superior ex vivo permeation (Cmax = 305.43 ± 32.07 µg.mL-1) and enhances in vivo dermato-pharmacokinetic parameters by 200-400 %. Drug content, hemolysis, and skin irritation studies confirmed its safety and non-toxicity.

Evaluation of antioxidant and antibacterial properties of dehydrocostus lactone isolated from Echinops kebericho root

Background and Aim

Echinops kebericho, an endemic plant to Ethiopia, traditionally used to treat infectious as well as noninfectious diseases. The primary objective of this study was isolating dehydrocostus lactone (DHCL) from E. kebericho and evaluating antibacterial activities on selected human pathogenic bacteria.

Methods

Extraction method used in this study was maceration. Based on the bioassay information methanol extract of the root of E. kebericho was subjected to column chromatography on silica gel by increasing solvent gradients to isolate DHCL. Optimized amount isolation of DHCL was done by dissolving methanol crude extract by hexane followed by recrystallization at room temperature in the dark place. Different concentrations of the extract were subjected by disc diffusion method against tested bacterial species and antioxidant activity test.

Results

The phytochemical analysis of E. kebericho revealed a high presence of terpenoids, which are diverse natural compounds known for their antimicrobial and antioxidant properties. This suggests that terpenoids contribute significantly to the pharmacological effects of E. kebericho. In antibacterial testing, Escherichia coli was the most sensitive bacterium among all extracts and concentrations. The methanol extract displayed higher antioxidant activity compared to ethyl acetate and hexane extracts, indicating a higher concentration of antioxidant compounds. Notably, the isolated compound DHCL showed promising activity against tested pathogens and significant antioxidant activity. The higher activity of DHCL compared to the crude extracts suggests its responsibility for the observed effects, indicating that the isolation and purification process may have concentrated its beneficial properties. These findings highlight the potential of E. kebericho and DHCL as sources of bioactive compounds for therapeutic applications.

Conclusion

All tested extracts and pure compound showed higher inhibition than positive controls in both bioassay. DHCL the principal bioactive component in the root extract of the plant and it displayed potent antibacterial and antioxidant activity.

Phytochemical screening, antioxidant activity of selected methanolic plant extracts and their detoxification capabilities against AFB1 toxicity

Aflatoxin B1 (AFB1) is a secondary metabolite produced principally by Aspergillus parasiticus and A. flavus. It is one of the most potent and commonly occurring dietary carcinogen with its carcinogenic potential being linked to the formation of DNA adducts and reactive oxygen species (ROS). Plant extracts contain a plethora of biologically active phytochemicals that act against ROS. This study aimed to assess the phytochemical content and antioxidant activity of methanolic extracts of some medicinal plants and investigate their detoxification potentials against AFB1. Phytochemical screening together with total phenolic content (TPC), total flavonoid content (TFC), and antioxidant (2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS+)) assays) were performed on nine methanolic plant extracts. Extracts were incubated with AFB1 for 24 and 48 h and liquid chromatography mass spectrometry (LC-MS) analysis done to assess their AFB1 detoxification activities. The TPC of the extracts ranged from 88.92 ± 6.54 to 210.19 ± 7.90 mg GAE/g, while TFC ranged between 4.01 ± 0.94 and 32.48 ± 1.02 mg QE/g. Radical scavenging activities of extracts varied from 4.18 ± 1.37 to 251.53 ± 9.30 μg/mL and 8.36 ± 1.65 to 279.22 ± 8.33 μg/mL based on DPPH and ABTS+ assays, respectively. Six of the plant extracts showed a time-dependent detoxification activity against AFB1 after 48 h ranging from 20.17 to 38.13 %. C. dentata bark extract showed the highest percentage of AFB1 reduction, with mean percentages of 43.57 and 70.96 % at 24 and 48 h, respectively. This was followed by C. asiatica leaves and A. melegueta seeds with a maximum of 40.81 and 38.13 %, respectively after 48 h. These extracts also possessed high TPC, TFC, and antioxidant activities compared to all the other extracts. Findings from this study demonstrate the abundance of bioactive compounds with antioxidant activity playing a role in potent AFB1 detoxification activity.

Immunomodulatory effects of epiphytic Loranthus micranthus leaf extracts collected from two host plants: Psidium guajava and Parkia biglobosa

BACKGROUND

Immunological abnormalities are implicated in the pathogenesis of many chronic diseases. Due to the drug-related adverse effects of currently available orthodox immunomodulators, natural immunomodulators are being looked upon as potential agents to replace them in therapeutic regimens. This research aimed to investigate the immunomodulatory potential of L. micranthus extracts epiphytic on Psidium guajava (LMPGE) and Parkia biglobosa (LMPBE).

METHODS

Phytochemical screening and acute toxicity testing were carried out to identify the phytoconstituents and safety profiles of the extracts. The extracts' innate and adaptive immunomodulatory potentials were determined in experimental animals using in vivo leucocyte mobilization, delayed-type hypersensitivity (DTH) response, hemagglutination antibody titre, and cyclophosphamide-induced myelosuppression models. Levamisole was used as the standard drug throughout the study.

RESULTS

Compared to LMPBE, LMPGE contained significantly (p <  0.05) more tannins, cyanogenic glycosides, saponins, reducing sugars, glycosides, flavonoids, and alkaloids. Furthermore, the groups treated with the extracts had a significant (p <  0.05) increase in the total number of leucocytes, neutrophils, basophils, and antibody titers relative to the untreated control. In the same way, the treatment raised TLC in cyclophosphamide-intoxicated rats, with 250 mg/kg b. w. of LMPGE and LMPBE recording 9712.50 ± 178.00 and 8000.00 ± 105.00 ×  109 /L, respectively, compared to 3425.00 ± 2 5.00 × 109 /L in the untreated group. Overall, LMPGE was more effective.

CONCLUSIONS

The findings from this study suggest that L. micranthus epiphytic in Psidium guajava and Parkia biglobosa has possible immune stimulating potential.