A triterpene saponin from Tribulus terrestris attenuates apoptosis in cardiocyte via activating PKC signalling transduction pathway

Hecogenin and its derivates: A pharmacology review

Despite the several uses of drugs from natural compounds in the pharmaceutical industry, new molecules have been discovered and associated with pharmacological activities over the years. Hecogenin, a steroidal saponin, has been the subject of several studies due to reports of pharmacological activities. This study combines the articles published to date that show the pharmacological activity and the mechanism of action of hecogenin, its acetate, and its derivates. This compilation shows that the compounds can act in different pathologies that affect many systems of the human body. They showed pharmacological properties in inflammation, mediating cytokines, cells, and environment. Also, it participated in tumoral processes by pathways like PPGARγ, ERK½, and MMP-2 and showed antimicrobial effects against organisms like Candida and Aedes aegypti's larvae. This review indicates that continuing studies with these molecules are essential once they have the potential to be a future drug.

Chemical Constituents, Biological Properties, and Uses of Tribulus terrestris: A Review

Tribulus terrestris L. (TT) (puncturevine) is a common weed that grows in many countries worldwide and in some places is considered as a noxious weed. The plant has been used in traditional Chinese and Indian medicines and is now considered as one of the most popular aphrodisiacs. It is known for its healing properties for sexual difficulties, impotence, and human and animal hormonal imbalance. It is also used as a sexual booster. Because of the plant’s active substances that can be used for curing sexual and other disorders, interest in it is increasing, and it is currently one of the most studied medicinal plants. The products and preparations manufactured from the aboveground plant parts are especially popular among athletes and people with health issues and diseases such as hormonal imbalance, sexual problems, heart problems, and various kidney and skin diseases. The aim of this review is a comprehensive and critical assessment of the scientific publications involving TT, with special reference to its chemical constituents and biological properties that may facilitate current understanding and future studies of this fascinating plant species. The objectives of this review were (1) to find knowledge gaps, (2) to discuss critically relevant publications and issues with materials and methods that may be prerequisites for contradictory results, and (3) to identify research and development areas. It was found that some of the studies on TT extracts as aphrodisiacs are controversial. A significant number of research publications claim that TT extracts and nutritional supplements containing TT improve muscle tone, have a common biostimulating effect, and improve spermogenesis. However, there are a growing number of publications that dispute these claims, as there are no empirical data on commonly accepted mechanisms of action. The main biologically active substances in TT are steroidal saponins, flavonoids, alkaloids, and lignan amides, the most studied being the steroidal saponins. Multiyear data on the metabolic profile of the species are generally lacking. There are a variety of methods used for extracting plant material, differences in methodologies and saponin analyses, and scientific instruments that were used. Lack of common standards could be a reason for differences in the pharmacological activity and composition of the TT preparations. Development of standard procedures and methods for collection of plant material and analyses are recommended. Selection and breeding efforts and agronomic studies of promising clones of TT would need to be conducted in order to develop TT as a new crop. This will provide consistency of supply and quality of the feedstock for the pharmaceutical industry and could provide a new cash crop for growers.

Structural characteristics, bioavailability and cardioprotective potential of saponins

Cardiovascular diseases are the leading cause of death, accounting about 31% deaths globally in 2012. The major risk factors causing cardiovascular diseases are coronary atherosclerosis, hyperlipidemia, myocardial infarction, and stroke. The dominating cause of cardiovascular diseases is accredited to our modern lifestyle and diet. Medicinal plants have been used for the prevention and treatment of cardiovascular diseases from centuries. The in built chirality and chemical space of natural products have been playing an important role in providing leads and templates for pharmacophore synthesis. This review highlights one of the important naturally occurring class saponins and their role in cardioprotection along with structural characteristics and pharmacological effects such as antioxidant, Ca²⁺ ion regulation, antiapoptotic, antiatherosclerosis, antihyperlipidemic, hypocholesterolemic, angiogenic, vasodilatory, and hypotensive. The characteristic cholesterol lowering, hemolytic, and anticoagulant properties of the saponins prompted us to select as one of the natural products class for cardioprotection. This review covers the most updated information on saponins related to their cardioprotective effects, mechanism of action, bioavailability, and structure activity relationship.

Tribulosin suppresses apoptosis via PKC epsilon and ERK1/2 signaling pathway during hypoxia/reoxygenation in neonatal rat ventricular cardiac myocytes

Tribulosin (tigogenin 3-O-β-D-xylopyranosyl(1-2)-[β-D-xylopyranosyl (1-3)]-β-D-glucopyranosyl (1-4)-[a-L-rhamnopyranosyl(1-2)]-β-D-galactopyranoside), a component of gross saponins of Tribulus terrestris, has been shown to produce cytoprotective effects in heart. Yet, the precise mechanisms are not fully understood. We examined the mechanisms of tribulosin on myocardial protection. Ventricular myocytes were isolated from the heart of neonatal rats and were exposed to 3 h of hypoxia followed by 2 h reoxygenation. Apoptosis was induced by hypoxia/reoxygenation (H/R), and the expression of protein kinase C epsilon (PKCϵ) and extracellular signal-regulated kinase 1 and 2 (ERK1/2) in cultured neonatal rat cardiac myocytes was detected. The results indicated that treatment with tribulosin in the culture medium protected cardiac myocytes against apoptosis induced by H/R. PKCϵ and ERK1/2 expression increased after pretreated with tribulosin. In the presence of PKCϵ inhibitor co-treated with tribulosin, the expression of ERK1/2 was decreased in H/R cardiac myocytes. While preconditioned with PD98059, ERK1/2 inhibitor, no effects on the expression of PKCϵ were detected. Tribulosin has protective effects on cardiac myocytes against apoptosis induced by H/R injury via PKCϵ and ERK1/2 signaling pathway.

Tribulosin protects rat hearts from ischemia/reperfusion injury

AIM

To investigate the protective effect of tribulosin, a monomer of the gross saponins from Tribulus terrestris, against cardiac ischemia/reperfusion injury and the underlying mechanism in rats.

METHODS

Isolated rat hearts were subjected to 30 min of ischemia followed by 120 min of reperfusion using Langendorff's technique. The hearts were assigned to seven groups: control, ischemia/reperfusion (I/R), treatment with gross saponins from Tribulus terrestris (GSTT) 100 mg/L, treatment with tribulosin (100, 10, and 1 nmol/L) and treatment with a PKC inhibitor (chelerythrine) (1 micromol/L). Infarct size was assessed by triphenyltetrazolium chloride staining. Malondialdehyde (MDA), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) contents as well as superoxide dismutase (SOD) and creatine kinase (CK) activities were determined after the treatment. Histopathological changes in the myocardium were observed using hematoxylin-eosin (H&E) staining. Apoptosis was detected with terminal deoxynucleotidyl transferase nick-end labeling (TUNEL) assay. Bcl-2, Bax, caspase-3, and PKCepsilon protein expression were examined using Western blotting.

RESULTS

Tribulosin treatment significantly reduced MDA, AST, CK and LDH contents, and increased the activity of SOD. The infarct size of I/R group was 40.21% of the total area. GSTT and various concentrations of tribulosin treatment decreased the infarct size to 24.33%, 20.24%, 23.19%, and 30.32% (P<0.01). Tribulosin treatment reduced the myocardial apoptosis rate in a concentration-dependent manner. Bcl-2 and PKCepsilon protein expression was increased after tribulosin preconditioning, whereas Bax and caspase-3 expression was decreased. In the chelerythrine group, Bcl-2 and PKCepsilon expression was decreased, whereas Bax and caspase-3 expression was increased.

CONCLUSION

Tribulosin protects myocardium against ischemia/reperfusion injury through PKCepsilon activation.