Dammarane triterpenoid glycosides in Bacopa monnieri: A review on chemical diversity and bioactivity

Methyl jasmonate inducible UGT79A18 is a novel glycosyltransferase involved in the bacoside biosynthetic pathway in Bacopa monnieri

Bacosides are dammarane-type triterpenoidal saponins in Bacopa monnieri and have various pharmacological applications. All the bacosides are diversified from two isomers, i.e., jujubogenin and pseudojujubogenin. The biosynthetic pathway of bacoside is not well elucidated. In the present study, we characterized a UDP-glycosyltransferase, UGT79A18, involved in the glycosylation of pseudojujubogenin. UGT79A18 shows higher expression in response to 5 h of wounding, and 3 h of MeJA treatment. The recombinant UGT79A18 shows in vitro activity against a wide range of flavonoids and triterpenes and has a substrate preference for protopanaxadiol, a dammarane-type triterpene. Secondary metabolite analysis of overexpression and knockdown lines of UGT79A18 in B. monnieri identify bacopasaponin D, bacopaside II, bacopaside N2 and pseudojujubogenin glucosyl rhamnoside as the major bacosides that were differentially accumulated. In the overexpression lines of UGT79A18, we found 1.7-fold enhanced bacopaside II, 8-fold enhanced bacopasaponin D, 3-fold enhanced pseudojujubogenin glucosyl rhamnoside, and 1.6-fold enhanced bacopaside N2 content in comparison with vector control plant, whereas in the knockdown lines of UGT79A18, we found 1.4-fold reduction in bacopaside II content, 3-fold reduction in the bacopasaponin D content, 2-fold reduction in the pseudojujubogenin glucosyl rhamnoside content, and 1.5-fold reduction in bacopaside N2 content in comparison with vector control. These results suggest that UGT79A18 is a significant UDP glycosyltransferase involved in glycosylating pseudojujubogenin and enhancing the pseudojujubogenin-derived bacosides.

Assessment of in vivo antiepileptic potential and phytochemical analysis of Cassia absus seed extracts

Cassia absus, a member of Fabaceae family, has been a part of traditional medicine for various ailments such as Hypertension, Diabetes, and Cancer. This family of plants has been utilized for Anticonvulsant and Anxiolytic effects. The ongoing investigation is aimed to seek the antiepileptic potential of C. absus seed extracts in pentylenetetrazole-induced kindling mice. The seeds of C. absus were subjected to a sequential extraction process for the preparation of n-hexane, chloroform, methanol, and aqueous extracts. The PTZ-induced kindling model was employed to assess the antiepileptic activity of each extract. Seizure activity and antioxidant biomarkers in the brain tissue such as levels of CAT, SOD, tGSH, and MDA were assessed. Mechanism of action was elucidated by Flumazenil. Through GC-MS analysis, the phytochemical components in the chloroform extract of C. absus were evaluated. The outcomes showed that C. absus extracts markedly reduced the seizure activity in kindling mice. The extracts exhibited significant Antioxidant properties by enhancing the levels of antioxidant biomarkers in the brain tissue such as CAT, SOD, and tGSH, and decreasing the MDA level. The results demonstrated that C. absus extracts showed antiepileptic effects may be via GABA pathway. According to the results of this investigation, C. absus has significant antiepileptic potential in PTZ-induced kindling mice via GABA pathway modulation and combating reactive oxygen species.

Micropropagation and elicited production of triterpenoid saponin glycosides and stigmasterol via precursor and elicitor feeding in Bacopa floribunda (R.Br.) Wettst.-A potential nootropic herb

Bacopa floribunda (Family: Plantaginaceae) is used in folklore medicines for the management of cognitive dysfunction. It has nootropic, antiaging, anti-inflammatory, anti-cholinesterase, and antioxidant properties. We developed an efficient and reproducible protocol for in vitro propagation of B. floribunda using the nodal explants. We assessed the effects of Murashige and Skoog (MS) medium fortified with various plant growth regulatory substances (PGRs), a precursor, and elicitors and their optimal combinations on regeneration and production of total saponins, triterpenoid saponin glycosides (bacoside A3, bacopaside X, bacopaside II, and bacosaponin C), and stigmasterol content in in vitro grown biomass of B. floribunda. The growth of the shoots and roots was stimulated by MS + 2.0 mg/l BAP + 2.0 mg/l KIN and MS + 0.5 mg/l IAA + 0.5 mg/l IBA + 1.0 mg/l NAA, respectively. After 10 weeks of acclimatization, plantlets of B. floribunda had a survival rate of 95%. The highest total saponin content (35.95 ± 0.022 mg DE/g DW) was noted in the treatment of MS + 2.0 mg/l BAP + 1.5 μM SQ. Similarly, total triterpenoid saponin glycosides and stigmasterol were found maximum in biomass derived from MS + 2.0 mg/l BAP + 1.5 μM SQ and MS + 2.0 mg/l BAP, respectively. At the same treatments, bacoside A3 (1.01 ± 0.195 mg/g DW), bacopaside II (43.62 ± 0.657 mg/g DW), bacopaside X (1.23 ± 0.570 mg/g DW), bacosaponin C (0.19 ± 0.195 mg/g DW), and stigmasterol (7.69 ± 0.102 mg/g DW) were reported. The present findings will help to highlight B. floribunda as a potent memory-enhancing herb, and in future also, it could be a potential substitute to B. monnieri. The current work is the first to describe the micropropagation and the elicited production of bioactive metabolites from the in vitro grown biomass of B. floribunda. In addition, further research is needed on production of bioactives, their pharmacological effects, and the elicited production using callus, cell suspension, and hairy root cultures.

Neuroprotective Potential of Bacopa monnieri: Modulation of Inflammatory Signals

BACKGROUND

To date, much evidence has shown the increased interest in natural molecules and traditional herbal medicine as alternative bioactive compounds to fight many inflammatory conditions, both in relation to immunomodulation and in terms of their wound healing potential. Bacopa monnieri is a herb that is used in the Ayurvedic medicine tradition for its anti-inflammatory activity.

OBJECTIVE

In this study, we evaluate the anti-inflammatory and regenerative properties of the Bacopa monnieri extract (BME) in vitro model of neuroinflammation.

METHODS

Neuronal SH-SY5Y cells were stimulated with TNFα and IFNγ and used to evaluate the effect of BME on cell viability, cytotoxicity, cytokine gene expression, and healing rate.

RESULTS

Our results showed that BME protects against the Okadaic acid-induced cytotoxicity in SH-SY5Y cells. Moreover, in TNFα and IFNγ primed cells, BME reduces IL-1β, IL-6, COX-2, and iNOS, mitigates the mechanical trauma injury-induced damage, and accelerates the healing of wounds.

CONCLUSION

This study indicates that BME might become a promising candidate for the treatment of neuroinflammation.

Pharmacological attributes of Bacopa monnieri extract: Current updates and clinical manifestation

Bacopa monnieri has been used for centuries in Ayurvedic medicine, alone or in combination with other herbs, as a memory and learning enhancer, sedative, and anti-epileptic. This review aimed to highlight the health benefits of B. monnieri extracts (BME), focusing on anti-cancer and neurodegenerative diseases. We examined the clinical studies on phytochemistry and pharmacological application of BME. We further highlighted the mechanism of action of these extracts in varying types of cancer and their therapeutic implications. In addition, we investigated the underlying molecular mechanism in therapeutic interventions, toxicities, safety concerns and synergistic potential in cognition and neuroprotection. Overall, this review provides deeper insights into the therapeutic implications of Brahmi as a lead formulation for treating neurological disorders and exerting cognitive-enhancing effects.

Biotechnological production of bacosides from cell and organ cultures of Bacopa monnieri

Bacopa monnieri (L.) Wettst. (BM), also known as 'Brahmi' or 'Water Hyssop', has been utilized as a brain tonic, memory enhancer, sensory organ revitalizer, cardiotonic, anti-anxiety, antidepressant and anticonvulsant agent in the Indian system of medicine Ayurveda for centuries. BM is beneficial in the treatment of Parkinson's disease, Alzheimer's disease, epileptic seizures and schizophrenia in recent pharmacological research. Dammarane-type triterpenoid saponins containing jujubogenin and pseudojujubogenin as aglycones, also known as bacosides, are the principal chemical ingredients identified and described from BM. Bacosides have been shown to have anti-ageing, anticancer, anticonvulsant, antidepressant, anti-emetic, anti-inflammatory and antibacterial properties in a variety of pre-clinical and clinical studies. The pharmaceutical industry's raw material comes from wild sources; nevertheless, the concentration of bacosides varies in different regions of the plants, as well as seasonal and genotypic variation. Cell and tissue cultures are appealing alternatives for the long-term manufacture of bioactive chemicals, and attempts to produce bacosides using in vitro cultures have been made. This review discusses the biotechnological approaches used to produce bacosides, as well as the limitations and future potential. KEY POINTS: • Bacosides extracted from Bacopa monnieri are important pharmaceutical compounds. • The current review provides insight into biotechnological interventions for the production of bacosides using in vitro cultures. • Highlights the prospects improvement of bacoside production through metabolic engineering.

Dammarane-type triterpenoid saponins from Salvia russellii Benth

Three undescribed dammarane-type saponins, russelliinosides A-C, together with a common sterol (β-sitosterol), an abietane diterpenoid (18-hydroxyferruginol), two oleane triterpenoids (daturaolone and oleanolic acid), an ursane triterpenoid (ursolic acid) as well as three 5-hydroxyflavones (cirsimaritin, eupatorin, and salvigenin) were isolated from a dichloromethane extract of the aerial parts of Salvia russellii Benth. The chemical structures of the aforementioned compounds were characterized, using detailed spectroscopic analyses, including high-resolution mass spectrometry and 1D and 2D NMR (1H-1H COSY, TOCSY, HSQC, HMBC and NOESY) spectroscopy as well as physicochemical properties. Cytotoxic effects of S. russellii extract and the three isolated russelliinosides were tested against MCF-7 human breast and A549 lung cancer, as well as non-cancer NIH/3T3 cells using MTT reduction assay. Russelliinosides A and B exhibited cytotoxic activities with IC50 values of 7.1 and 30.7 μg/ml against MCF-7 and 33.9 and 69.4 μg/ml against A549 cells, respectively, while russelliinoside C did not show cytotoxicity against cancer cells. On the other hand, russelliinoside A showed an IC50 value of 31.5 μg/ml against NIH/3T3 cells, while russelliinosides B and C had no effect on the viability of these non-cancer cells.

Bioactive dammarane triterpenoid saponins from the leaves of Cyclocarya paliurus

Thirteen undescribed dammarane triterpenoid saponins (cypaliurusides A-M), including eleven seco-dammarane type triterpenoids, were isolated from Cyclocarya paliurus. Each of these compounds has the unique feature of having a monosaccharide attached to C-11, rather than C-12, compared to the same type of saponins found in this plant. The structures of them were determined by comprehensive analysis of 1D, 2D NMR and HRESIMS data. Cypaliuruside J showed significant α-glucosidase inhibitory effect with IC50 value of 2.22 ± 0.13 μM. In addition, Cypaliurusides F and K exhibited modest cytotoxic activities against selected human cancer cell lines in vitro, with IC50 values ranging from 4.61 ± 0.13 to 15.23 ± 3.88 μM.

Amyloid β aggregation inhibitory activity of triterpene saponins from the cactus Stenocereus pruinosus

Six new triterpene saponins (1-5,7) and 3 known saponins (6,8,9) were isolated from MeOH extracts of the cactus Stenocereus pruinosus. The structures of the isolated saponins were elucidated using MS, IR, and comprehensive NMR measurements. To develop drugs for treating Alzheimer's disease (AD) on the basis of the amyloid cascade hypothesis, the isolated saponins were evaluated for inhibition of BACE1 activity and amyloid beta (Aβ) aggregation using thioflavin-T assay, and triterpenes as an aglycone moiety and an alkaline hydrolysate of the saponins were also evaluated. One saponin, stenoside A (7), exhibited inhibitory activity related to Aβ aggregation and its degree of Aβ aggregation was 40.6% at 100 μM.

Capturing Dioclea Reflexa Seed Bioactives on Halloysite Nanotubes and pH Dependent Release of Cargo against Breast (MCF-7) Cancers In Vitro

In this work, optimization parameters were developed to capture plant metabolites from Dioclea Reflexa (DR) seed ex-tracts onto halloysites nanotubes (HNTs). A one-step pool of the crude extracts at neutral pH from the HNT lumen failed to elicit a reduction in breast cancer, Michigan Cancer Foundation-7 (MCF-7) cell viability. However, the pH-dependent elution of metabolites revealed that the acidic pH samples exhibited profound antiproliferative effects on the cancer cells compared to the basic pH metabolites using both trypan blue dye exclusion assay and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) viability test. pH~5.2 samples demonstrated by half-maximal inhibitory concentration (IC50) of 0.8 mg and a cyclic voltammetry oxidation peak potential and current of 234 mV and 0.45 µA, respectively. This indicates that the cancer cells death could be attributed to membrane polarization/depolarization effects of the sample. Fluorescence-activated cell sorting (FACS) studies confirmed that the plant metabolites affected breast cancer apoptotic signaling pathways of cell death. The studies proved that plant metabolites could be captured using simplified screening procedures for rapid drug discovery purposes. Such procedures, however, would require the integration of affordable analytical tools to test and isolate individual metabolites. Our approach could be an important strategy to create a library and database of bioactive plant metabolites based on pH values.