Biomimetic Chromatographic Studies Combined with the Computational Approach to Investigate the Ability of Triterpenoid Saponins of Plant Origin to Cross the Blood–Brain Barrier

Biomimetic (non-cell based in vitro) and computational (in silico) studies are commonly used as screening tests in laboratory practice in the first stages of an experiment on biologically active compounds (potential drugs) and constitute an important step in the research on the drug design process. The main aim of this study was to evaluate the ability of triterpenoid saponins of plant origin to cross the blood–brain barrier (BBB) using both computational methods, including QSAR methodology, and biomimetic chromatographic methods, i.e., High Performance Liquid Chromatography (HPLC) with Immobilized Artificial Membrane (IAM) and cholesterol (CHOL) stationary phases, as well as Bio-partitioning Micellar Chromatography (BMC). The tested compounds were as follows: arjunic acid (Terminalia arjuna), akebia saponin D (Akebia quinata), bacoside A (Bacopa monnieri) and platycodin D (Platycodon grandiflorum). The pharmacokinetic BBB parameters calculated in silico show that three of the four substances, i.e., arjunic acid, akebia saponin D, and bacoside A exhibit similar values of brain/plasma equilibration rate expressed as logPSFubrain (the average logPSFubrain: −5.03), whereas the logPSFubrain value for platycodin D is –9.0. Platycodin D also shows the highest value of the unbound fraction in the brain obtained using the examined compounds (0.98). In these studies, it was found out for the first time that the logarithm of the analyte–micelle association constant (logKMA) calculated based on Foley’s equation can describe the passage of substances through the BBB. The most similar logBB values were obtained for hydrophilic platycodin D, applying both biomimetic and computational methods. All of the obtained logBB values and physicochemical parameters of the molecule indicate that platycodin D does not cross the BBB (the average logBB: 1.681), even though the in silico estimated value of the fraction unbound in plasma is relatively high (0.52). As far as it is known, this is the first paper that shows the applicability of biomimetic chromatographic methods in predicting the penetration of triterpenoid saponins through the BBB.

Bacoside-A exerts protective effect against Parkinson’s disease-induced functional damage in mice via inhibition of apoptosis and oxidative response

Purpose: To determine the effect of bacoside-A on Parkinson's disease (PD) in a rat model, and elucidate its mechanism of action.Methods: A rat model of PD was established by administration of 5 µL of 6-hydroxydopamine in ascorbic acid (0.1 %). Measurement of serum levels of inflammatory factors was carried out using enzyme-linked immunosorbent assay (ELISA) kits. Western blotting was used to assay Bax, cytochrome c and Bcl-2 in rat hippocampus.Results: Bacoside-A treatment significantly reduced PD-induced high turning values in rats (p < 0.05). Treatment with bacoside-A reversed PD-mediated suppression of serum activities of CAT and glutathione peroxidase (GPx). In bacoside-A-treated PD rats, dose-dependent suppression of acetylcholinesterase (AChE) and inducible nitric oxide synthase (iNOS) activities were observed (p < 0.05). Bacoside-A-treated PD rats significantly (p < 0.018) reduced interleukin (IL)-1β and IL-6 levels. Treatment of PD rats with bacoside-A effectively reduced levels of tumor necrosis factor (TNF)-α, NF-κB p65, (COX)-2 and p53 protein, and also reversed up-regulations of Bax, cytochrome C, caspase-3 and caspase-9.Conclusion: Bacoside-A exhibits a protective effect against Parkinson disease-induced oxidative damage and neuronal degeneration in rats through downregulation of iNOS, AChE, inflammatory cytokines and pro-apoptotic proteins. Therefore, bacoside-A has potentials for use in the management of Parkinson disease. Keywords: Parkinson disease, Neuroprotective, Pro-apoptotic, Cytokines, Neurotoxicity

Defensive proclivity of bacoside A and bromelain against oxidative stress and AChE gene expression induced by dichlorvos in the brain of Mus musculus

The objective of current study was to evaluate the neuroprotective effects of bacoside A and bromelain against dichlorvos induced toxicity. The healthy, 6–8 weeks old male Swiss mice were administered in separate groups subacute doses of dichlorvos (40 mg/kg bw), bacoside A (5 mg/kg bw) and bromelain (70 mg/kg bw). In order to determination of oxidative stress in different groups, thiobarbituric acid reactive substances (TBARS) and protein carbonyl content (PCC) were studied in the present investigation. Moreover, for toxic manifestation at molecular level the site-specific gene amplification of acetylcholinesterase (AChE) gene was studied in the brain. Nonetheless, the protective effects of bacoside A and bromelain were also evaluated on the TBARS, PCC and AChE gene. The exposure of dichlorvos leads to significant increase in TBARS level (p < 0.01, p < 0.001) and PCC. Besides, the decline in DNA yield, expression of amplified products of AChE gene was observed in the brain of dichlorvos treated group. The bacoside A and bromelain treatments significantly decreased the level of TBARS (p < 0.05, (p < 0.01) and PCC whereas, increase in the DNA yield and expression of amplified AChE gene products were observed in the brain compared to only dichlorvos treated mice. The overall picture which emerged after critical evaluation of results indicated that the dichlorvos induced oxidative stress and alteration in AChE gene expression showed significant improvement owing to the treatments of bacoside A and bromelain. Thus, bacoside A and bromelain are very effective in alleviating neurotoxicity induced by dichlorvos.

Development and Validation of a Novel, Rapid Gradient HPLC Method for Simultaneous Estimation of Bioactive Marker Compounds in a Mixture of Convolvulus pluricaulis, Withania somnifera and Bacopa monnieri Extracts

The use of herbs as medicine is an ancient form of healthcare known to mankind. Standardization of herbal medicines is however a challenging task and is the major bottleneck in their acceptance as the primary therapeutic option. The aim of this study was to develop and validate a simple, rapid HPLC method for standardizing the mixture of extracts of three Medhya Rasayanas (neurotonic), Convolvulus pluricaulis, Withania somnifera and Bacopa monnieri. Simultaneous estimation of the respective bioactive markers of these plants viz., scopoletin, withaferin A, bacoside A 3, bacopaside II, jujubogenin and bacosaponin C has been reported for the first time. The method was developed using Waters Hybrid X-Bridge shield with BEH technology 2.5 μm, 4.6 × 75 mm column and validated according to ICH guidelines. The 20 minutes run time makes the method eco-friendly. The method was linear over a range of 12.5–400 ng/10 μL for scopoletin and 62.5–2,000 ng/10 μL for withaferin A, bacoside A 3, bacopaside II, jujubogenin and bacosaponin C with detection limits of 8.0, 48.3, 30.4, 40.7, 15.6 and 18.9 ng/10 μL and quantification limits of 24.5, 146.5, 92.2, 123.4, 47.4 and 57.4 ng/10 μL, respectively. The correlation coefficient for each analyte was &gt;0.999. The intra-day and inter-day precision was &lt;2%. These results confirmed the precision, accuracy and robustness of the proposed method.