Simultaneous HPTLC analysis of ursolic acid, betulinic acid, stigmasterol and lupeol for the identification of four medicinal plants commonly available in the Indian market as Shankhpushpi

Carbon dot unravels accumulation of triterpenoid in Evolvulus alsinoides hairy roots culture by stimulating growth, redox reactions and ANN machine learning model prediction of metabolic stress response

Evolvulus alsinoides, a therapeutically valuable shrub can provide consistent supply of secondary metabolites (SM) with pharmaceutical significance. Nonetheless, because of its short life cycle, fresh plant material for research and medicinal diagnostics is severely scarce throughout the year. The effects of exogenous carbon quantum dot (CD) application on metabolic profiles, machine learning (ML) prediction of metabolic stress response, and SM yields in hairy root cultures of E. alsinoides were investigated and quantified. The range of the particle size distribution of the CDs was between 3 and 7 nm. The CDs EPR signal and spin trapping experiments demonstrated the formation of O2-•spin-adducts at (g = 2.0023). Carbon dot treatment increased the levels of hydrogen peroxide and malondialdehyde concentrations as well as increased antioxidant enzyme activity. CD treatments (6 μg mL-1) significantly enhanced the accumulation of squalene and stigmasterol (7 and 5-fold respectively). The multilayer perceptron (MLP) algorithm demonstrated remarkable prediction accuracy (MSE value = 1.99E-03 and R2 = 0.99939) in both the training and testing sets for modelling. Based on the prediction, the maximum oxidative stress index and enzymatic activities were highest in the medium supplemented with 10 μg mL-1 CDs. The outcome of this study indicated that, for the first time, using CD could serve as a novel elicitor for the production of valuable SM. MLP may also be used as a forward-thinking tool to optimize and predict SM with high pharmaceutical significance. This study would be a touchstone for understanding the use of ML and luminescent nanomaterials in the production and commercialization of important SM.

Stigmasterol: An Enigmatic Plant Stress Sterol with Versatile Functions

Sterols play important structural and regulatory roles in numerous intracellular processes. Unlike animals, plants contain a distinctive and diverse variety of sterols. Recently, information has emerged showing that stigmasterol is a "stress sterol". Stigmasterol is synthesized via the mevalonate biosynthesis pathway and has structural similarity to β-sitosterol but differs in the presence of a trans-oriented double bond in the side chain. In plants, the accumulation of stigmasterol has been observed in response to various stresses. However, the precise ways that stigmasterol is involved in the stress responses of plants remain unclear. This comprehensive review provides an update on the biology of stigmasterol, particularly the physicochemical properties of this ethylsterol, its biosynthesis, and its occurrence in higher plants and extremophilic organisms, e.g., mosses and lichens. Special emphasis is given to the evolutionary aspects of stigmasterol biosynthesis, particularly the variations in the gene structure of C22-sterol desaturase, which catalyzes the formation of stigmasterol from β-sitosterol, in a diversity of evolutionarily distant organisms. The roles of stigmasterol in the tolerance of plants to hostile environments and the prospects for its biomedical applications are also discussed. Taken together, the available data suggest that stigmasterol plays important roles in plant metabolism, although in some aspects, it remains an enigmatic compound.

Effect of Ursolic and Oleanolic Acids on Lipid Membranes: Studies on MRSA and Models of Membranes

Staphylococcus aureus is an opportunistic pathogen and the major causative agent of life-threatening hospital- and community-acquired infections. A combination of antibiotics could be an opportunity to address the widespread emergence of antibiotic-resistant strains, including Methicillin-Resistant S. aureus (MRSA). We here investigated the potential synergy between ampicillin and plant-derived antibiotics (pentacyclic triterpenes, ursolic acid (UA) and oleanolic acid (OA)) towards MRSA (ATCC33591 and COL) and the mechanisms involved. We calculated the Fractional Inhibitory Concentration Index (FICI) and demonstrated synergy. We monitored fluorescence of Bodipy-TR-Cadaverin, propidium iodide and membrane potential-sensitive probe for determining the ability of UA and OA to bind to lipoteichoic acids (LTA), and to induce membrane permeabilization and depolarization, respectively. Both pentacyclic triterpenes were able to bind to LTA and to induce membrane permeabilization and depolarization in a dose-dependent fashion. These effects were not accompanied by significant changes in cellular concentration of pentacyclic triterpenes and/or ampicillin, suggesting an effect mediated through lipid membranes. We therefore focused on membranous effects induced by UA and OA, and we investigated on models of membranes, the role of specific lipids including phosphatidylglycerol and cardiolipin. The effect induced on membrane fluidity, permeability and ability to fuse were studied by determining changes in fluorescence anisotropy of DPH/generalized polarization of Laurdan, calcein release from liposomes, fluorescence dequenching of octadecyl-rhodamine B and liposome-size, respectively. Both UA and OA showed a dose-dependent effect with membrane rigidification, increase of membrane permeabilization and fusion. Except for the effect on membrane fluidity, the effect of UA was consistently higher compared with that obtained with OA, suggesting the role of methyl group position. All together the data demonstrated the potential role of compounds acting on lipid membranes for enhancing the activity of other antibiotics, like ampicillin and inducing synergy. Such combinations offer an opportunity to explore a larger antibiotic chemical space.

HPLC Coupled with Chemometric Analysis and LC–MS Studies of Three Flavonoids in Tephrosia purpurea (L.) Pers Revealed Impact of Chemodiversity on the Quest for the Chemical Markers

Globally, Tephrosia purpurea (L.) Pers is used as an important component in herbal drug formulations for liver health. The present study is aimed to develop a suitable analytical approach for simultaneous analysis of three flavonoids (rutin, deguelin and rotenone) to establish quality control methods for plant. A novel High-performance liquid chromatography photodiode array detector (HPLC-PDA) method has been developed to quantify these flavonoids in T. purpurea. The method was validated, and data were subjected to chemometric analysis to select most optimal marker compound. The method that was found linear with R2 values ranges from 0.996 to 0.998 with good recoveries. Intra- and inter-day precision values were <2. HPLC analysis revealed high level of chemodiversity. Quantity of all the three chemical markers was found significantly disparate in samples from different locations. Deguelin was detectable only in three out of total eight samples. However, liquid chromatography–mass spectrometry analysis was found sufficiently sensitive to detect all the compounds in all samples. Thus, results suggest to apply combination of approaches to enhance confidence in chromatographic methods for quality control of herbal drugs. Principal component analysis ranked the markers as Rutin>Rotenone>Deguelin. This comprehensive approach employing multichromatography platforms can be successfully utilized in analysis of these bioactive markers and routine standardization of herbal material and formulations containing T. purpurea.

Biological Evaluation of Different Extracts of Aerial Parts of Nepeta deflersiana and Standardization of Active Extracts Using 8-Epi-7-Deoxyloganic Acid and Ursolic Acid by Validated HPTLC Method

Nepeta deflersiana (Lamiaceae) is a well-known medicinal plant that grows in Saudi Arabia. This plant is used in Saudi and Yemeni folk medicine as an anti-inflammatory, carminative, and antirheumatic agent. In order to prove its use in folk medicine, four different extracts from the aerial parts of the plant: petroleum ether, chloroform, ethyl acetate, and n-butanol extracts were subjected to biological assays to screen PPARα and PPAR_ϒ agnostic, antioxidant, anti-inflammatory, and cytotoxic activities. Ethyl acetate and n-butanol extracts of N. deflersiana NDEE and NDBE, respectively, showed a decrease in oxidative stress and inhibition of both NF-kB and iNOS activities with no cytotoxic effects on four human cancer cell lines. Both active extracts were standardized using two bioactive metabolites which were isolated from the aerial parts of the same plant [8-epi-7-deoxyloganic acid (compound 1) and Ursolic acid (compound 2)] by developing a validated HPTLC method. It was found to provide a sharp and compact band of compound 1 at R_f = 0.07 and R_f = 0.57 for compound 2, using chloroform, methanol, and formic acid (8.9:0.8:0.3, v/v/v) as mobile phase at 550 nm. Compounds 1 and 2 were found in NDEE by 9.59 %, w/w, and 84.63 %, w/w, respectively, and by 11.97 %, w/w, and 21.26 %, w/w, respectively, in NDBE.

Neuropharmacological evaluation on four traditional herbs used as nervine tonic and commonly available as Shankhpushpi in India

Background

Shankhpushpi is an Ayurvedic drug, widely used for its actions on the central nervous system, especially to improve intellect and boost memory. Four botanicals viz. Canscora decussata Schult. (CD), Clitorea ternatea Linn. (CT), Convolvulus pluricaulis Choisy. (CP) and Evolvulus alsinoides Linn. (EA) are considered as sources of Shankhpushpi by Indian practitioners on the basis of their morphological descriptions given in ancient texts.

Objective

The present study was undertaken to evaluate the neuropharmacological effect of four herbs commonly identified as source of Shankhpushpi.

Materials and methods

Methanol extracts of all four varieties were tested and evaluated in vitro and in vivo for their neuropharmacological effects. Experiments such as protection against β-amyloid induced neurotoxicity on brain cell line (Neuro 2A), antioxidant potential, AchE (acetylcholinesterase enzyme) inhibition, and 5-LOX (lipoxygenase) enzyme inhibition were conducted for in vitro evaluation. For in vivo evaluation, scopolamine (0.3 mg/kg i.p.) induced memory retrieval using pole climbing apparatus and Morris water maze were performed in rat models.

Results

It was found that protective effects of EA and CD against β-amyloid induced neurotoxicity in Neuro 2A cells were significantly higher than CT and CP. EA proved to be superior than other varieties on the basis of antioxidant activity, AchE inhibitory and LOX inhibitory activities. The preventive activity of EA on scopolamine induced memory retrieval in pole climbing and Morris water maze task in rats was found to be higher than that of CD, CT and CP.

Conclusion

EA has remarkable neuropharmacological effect as compared to other three varieties of Shankhpushpi. This effect may be attributed due to the presence of steroids (stigmasterol and betulinic acid), coumarins (scopoletin) and flavonoids (β-carotene and chlorogenic acid). Hence it can be used as a promising lead in development and management of neuronal disorders including Alzheimer's disease.

Optimization of extraction parameters of pentacyclic triterpenoids from Swertia chirata stem using response surface methodology

In the present investigation, pentacyclic triterpenoids were extracted from different parts of Swertia chirata by solid-liquid reflux extraction methods. The total pentacyclic triterpenoids (UA, OA, and BA) in extracted samples were determined by HPTLC method. Preliminary studies showed that stem part contains the maximum pentacyclic triterpenoid and was chosen for further studies. Response surface methodology (RSM) has been employed successfully by solid-liquid reflux extraction methods for the optimization of different extraction variables viz., temperature (X₁ 35-70 °C), extraction time (X₂ 30-60 min), solvent composition (X₃ 20-80%), solvent-to-solid ratio (X₄ 30-60 mlg^-1), and particle size (X₅ 3-6 mm) on maximum recovery of triterpenoid from stem parts of Swertia chirata. A Plackett-Burman design has been used initially to screen out the three extraction factors viz., particle size, temperature, and solvent composition on yield of triterpenoid. Moreover, central composite design (CCD) was implemented to optimize the significant extraction parameters for maximum triterpenoid yield. Three extraction parameters viz., mean particle size (3 mm), temperature (65 °C), and methanol-ethyl acetate solvent composition (45%) can be considered as significant for the better yield of triterpenoid A second-order polynomial model satisfactorily fitted the experimental data with the R² values of 0.98 for the triterpenoid yield (p < 0.001), implying good agreement between the experimental triterpenoid yield (3.71%) to the predicted value (3.79%).

Isolation and Simultaneous Quantification of Nine Triterpenoids from Rosa davurica Pall

Rosa davurica Pall. has been used as a traditional Oroqen medicine to treat dyspepsia, gastroenterologia, menoxenia and other diseases. In this study, the chemical constituents research on the fruit pulp of R. davurica led to the isolation and identification of nine bioactive pentacyclic triterpenoids and five of them were isolated from the plant for the first time. Subsequently a simple and rapid high-performance liquid chromatography (HPLC) method was established for the simultaneous quantification of the nine triterpenoids. The separation was performed on a Merges reverse phase (RP) C₁₈ (250 × 4.6 mm, 5 μm) column through 40 min gradient delivery of 0.05% phosphoric acid aqueous solution and acetonitrile at a flow rate of 1.2 mL/min at 30°C and the detection wavelength selected was 210 nm. All of the calibration curves showed good linearity (R² > 0.9990) in the tested ranges. The limit of detection and the limit of quantitation were in the range of 0.21-1.27 μg/mL and 0.63-3.80 μg/mL, respectively. The established method also showed good precision, repeatability and recovery and can be used to the routine quality control of R. davurica and other herbs containing pentacyclic triterpenoids.

A Validated HPTLC Densitometric Method for Simultaneous Determination of Evernic and Usnic Acids in Four Usnea Species and Comparison of Their Antioxidant Potential

A simple, sensitive and precise high-performance thin-layer chromatography method with densitometric detection was used for simultaneous determination of evernic (EV) and (+)-usnic acids (USN) in Usnea aciculifera (UA), U. ghattensis (UG), U. longissima (UL) and U. stigmatoides (US). This method was also validated according to the ICH guidelines. Separation and quantification was performed with the mobile phase toluene-1, 4-dioxane-formic acid (18:4.5:0.2, v/v/v) on silica gel 60F254 plates. The linearity for EV and USN was found in the 200-600 ng/band range. The limit of detection for EV and USN was 51.56 and 32.59 ng/band, while the limit of quantification was 156.23 and 98.76 ng/band, respectively. Intra- and interday precisions (n = 6) for EV and USN were 0.70-1.89 and 0.50-0.76 (%RSD), and 1.56-1.60 and 1.54-1.99 (%RSD), respectively. The mean percent recoveries were 99.66 and 99.87%, respectively, for EV and USN. However, USN was estimated in all four Usnea species but EV only in two species with varied quantity. Comparative antioxidant activity revealed that US is a better free radical scavenger in comparison with other three Usnea species. Furthermore, these results indicated that USN and EV are not solely responsible for antioxidant potential, but it may be due to synergistic effect.

Internal transcribed spacer guided multiplex PCR for species identification of Convolvulus prostratus and Evolvulus alsinoides

Shankhpushpi is a reputed drug from an Indian system of medicine for treating mental disorders and enhancing memory. Two herbs, namely Convolvulus prostratus Forssk. and Evolvulus alsinoides (L.) L., are commonly known as Shankhpushpi. Ambiguous vernacular identity can affect the scientific validity of the Shankpushpi-based herbal drug therapy. In the present investigation, a novel and sensitive multiplex PCR method based on polymorphism in the internal transcribed spacer (ITS) region was developed to establish the molecular identity of C. prostratus and E. alsinoides. DNA was isolated and the ITS region was amplified, sequenced and assembled. Sequences were aligned to identify variable nucleotides in order to develop plant-specific primers. Primers were validated in singleplex reactions and eventually a multiplex assay was developed. This assay was tested for sensitivity and validated by amplifying DNA isolated from the simulated blended powdered plant material. Primers developed for C. prostratus resulted into a 200 bp amplicon and 596 bp for E. alsinoides. The assay was found to be sensitive enough for amplification of low quantities of DNA. The method can detect 10% of the mixing of plants with each other in blended material. This PCR assay can be used for rapid botanical identification of Shankhpushpi plant materials and will improve evidence-based herbal drug therapy.

Antioxidant and hepatoprotective effects of mixed micellar lipid formulation of phyllanthin and piperine in carbon tetrachloride-induced liver injury in rodents

Phyllanthin, a sparingly water-soluble hepatoprotective lignin obtained from Phyllanthus amarus Schum. et Thonn. (Euphorbiaceae) possesses low bioavailability.