In Vivo Antistress Effects of Synthetic Flavonoids in Mice: Behavioral and Biochemical Approach

Preparing a novel baicalin-loaded microemulsion-based gel for transdermal delivery and testing its anti-gout effect

We previously demonstrated that baicalin had efficacy against gouty arthritis (GA) by oral administration. In this paper, a novel baicalin-loaded microemulsion-based gel (B-MEG) was prepared and assessed for the transdermal delivery of baicalin against GA. The preparation method and transdermal capability of B-MEG was screened and optimized using the central composite design, Franz diffusion cell experiments, and the split-split plot design. Skin irritation tests were performed in guinea pigs. The anti-gout effects were evaluated using mice. The optimized B-MEG comprised of 50 % pH 7.4 phosphate buffered saline, 4.48 % ethyl oleate, 31.64 % tween 80, 13.88 % glycerin, 2 % borneol, 0.5 % clove oil and 0.5 % xanthan gum, with a baicalin content of (10.42 ± 0.08) mg/g and particle size of (15.71 ± 0.41) nm. After 12 h, the cumulative amount of baicalin permeated from B-MEG was (672.14 ± 44.11) μg·cm-2. No significant skin irritation was observed following B-MEG application. Compared to the model group, B-MEG groups significantly decreased the rate of auricular swelling (P < 0.01) and number of twists observed in mice (P < 0.01); and also reduced the rate of paw swelling (P < 0.01) and inflammatory cell infiltration in a mouse model of GA. In conclusion, B-MEG represents a promising transdermal carrier for baicalin delivery and can be used as a potential therapy for GA.

Synthetic Mono-Carbonyl Curcumin Analogues Attenuate Oxidative Stress in Mouse Models

Alzheimer’s disease is the commonest form of dementia associated with short-term memory loss and impaired cognition and, worldwide, it is a growing health issue. A number of therapeutic strategies have been studied to design and develop an effective anti-Alzheimer drug. Curcumin has a wide spectrum of biological properties. In this regard, the antioxidant potentials of mono-carbonyl curcumin analogues (h1−h5) were investigated using in vitro antioxidant assays and hippocampal-based in vivo mouse models such as light−dark box, hole board, and Y-maze tests. In the in vitro assay, mono-carbonyl curcumin analogues h2 and h3 with methoxy and chloro-substituents, respectively, showed promising 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2′-azinobis-3-ethylbenzothiazo-line-6-sulfonate (ABTS) free radical scavenging activities. In the in vivo studies, scopolamine administration significantly (p < 0.001) induced oxidative stress and memory impairment in mice, in comparison to the normal control group. The pretreatment with mono-carbonyl curcumin analogues, specifically h2 and h3, significantly decreased (123.71 ± 15.23 s (p < 0.001), n = 8; 156.53 ± 14.13 s (p < 0.001), n = 8) the duration of time spent in the light chamber and significantly enhanced (253.95 ± 19.05 s (p < 0.001), n = 8, and 239.57 ± 9.98 s (p < 0.001), n = 8) the time spent in the dark compartment in the light−dark box arena. The numbers of hole pokings were significantly (p < 0.001, n = 8) enhanced in the hole board test and substantially increased the percent spontaneous alternation performance (SAP %) in the Y-maze mouse models in comparison to the stress control group. In the biomarker analysis, the significant reduction in the lipid peroxidation (MDA) level and enhanced catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH) activities in the brain hippocampus reveal their antioxidant and memory enhancing potentials. However, further research is needed to find out the appropriate mechanism of reducing oxidative stress in pathological models.

Investigation of Antistress and Antidepressant Activities of Synthetic Curcumin Analogues: Behavioral and Biomarker Approach

Depression is a serious psychiatric disorder that affects millions of individuals all over the world, thus demanding special attention from researchers in order to investigate its effective remedies. Curcumin, along with its synthetic derivatives, is recognized for its incredible pharmacological activities. In this study, methyl, methoxy and chloro-substituent synthetic curcumin analogues C1-C3 were respectively tested for free radical-scavenging activity. Behavioral studies were performed using chemical-induced and swimming endurance tests as stress models, and forced swim tests (FSTs) and tail suspension tests (TSTs) as depression mice models. Biochemical examinations were performed after a scopolamine-induced stress model by decapitating the mice, and brain tissues were isolated for biochemical assessment of catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA). The curcumin analogue C2 exhibited higher DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azinobis-3-ethylbenzothiazo-line-6-sulphonate) free radical-scavenging potential, having IC50 values of 45.18 µg/mL and 62.31 µg/mL, respectively, in comparison with reference curcumin and tocopherol. In the chemical-induced test, C2 (80.17%), C3 (72.79%) and C1 (51.85%) revealed higher antistress responses by significantly reducing the number of writhes, whereas the immobility time was significantly reduced by C2 and C3 in the swimming endurance test, indicating excellent antistress potential. Similarly, C2 and C3 significantly reduced the immobility times in FST and TST, demonstrating their antidepressant properties. The biomarkers study revealed that these compounds significantly enhanced hippocampus CAT, SOD and GSH, and reduced MDA levels in the scopolamine-induced stress mice model. These findings suggest the potential of curcumin analogues (C2 and C3) as antistress and antidepressant agents.