Aqueous extract of pomegranate seed attenuates glucocorticoid-induced bone loss and hypercalciuria in mice: A comparative study with alendronate

Pomegranate seeds: a comprehensive review of traditional uses, chemical composition, and pharmacological properties

Pomegranate seeds (PS) are the dried seeds derived from pomegranate fruit, accounting for approximately 20% of the fruit's total weight, and are a by-product of pomegranate juice extraction. These seeds hold significance in traditional medicine among Uyghurs and Tibetan cultures, featuring diverse clinical applications within traditional Chinese medicine. These applications include management of gastric coldness and acidity, abdominal distension, liver and gallbladder fever, and pediatric enteritis. PS demonstrates properties such as stomach tonicity, qi regulation, analgesia, and anti-inflammatory effects. Extensive research underscores the richness of PS in various phytochemical compounds and metabolites, notably unsaturated fatty acids (particularly linolenic acid and linoleic acid), phenolic compounds tocopherols, proteins, and volatile oils. Notably, among these bioactive compounds, punicic acid (PA), found within PS, demonstrates potential in the prevention and treatment of cancers, diabetes, obesity, and other ailments. Despite extensive literature on pomegranate as a botanical entity, a comprehensive review focusing specifically on the chemical composition and pharmacological effects of PS remains elusive. Therefore, this review aimed to consolidate knowledge regarding the medicinal properties of PS, summarizing its chemical composition, traditional uses, and pharmacological effects in treating various diseases, thereby laying a foundation for the advancement and application of PS in the field of pharmacology.

Calcium selective channel TRPV6: Structure, function, and implications in health and disease

Calcium-selective channel TRPV6 (Transient Receptor Potential channel family, Vanilloid subfamily member 6) belongs to the TRP family of cation channels and plays critical roles in transcellular calcium (Ca2+) transport, reuptake of Ca2+ into cells, and maintaining a local low Ca2+ environment for certain biological processes. Recent crystal and cryo-electron microscopy-based structures of TRPV6 have revealed mechanistic insights on how the protein achieves Ca2+ selectivity, permeation, and inactivation by calmodulin. The TRPV6 protein is expressed in a range of epithelial tissues such as the intestine, kidney, placenta, epididymis, and exocrine glands such as the pancreas, prostate and salivary, sweat, and mammary glands. The TRPV6 gene is a direct transcriptional target of the active form of vitamin D and is efficiently regulated to meet the body's need for Ca2+ demand. In addition, TRPV6 is also regulated by the level of dietary Ca2+ and under physiological conditions such as pregnancy and lactation. Genetic models of loss of function in TRPV6 display hypercalciuria, decreased bone marrow density, deficient weight gain, reduced fertility, and in some cases alopecia. The models also reveal that the channel plays an indispensable role in maintaining maternal-fetal Ca2+ transport and low Ca2+ environment in the epididymal lumen that is critical for male fertility. Most recently, loss of function mutations in TRPV6 gene is linked to transient neonatal hyperparathyroidism and early onset chronic pancreatitis. TRPV6 is overexpressed in a wide range of human malignancies and its upregulation is strongly correlated to tumor aggressiveness, metastasis, and poor survival in selected cancers. This review summarizes the current state of knowledge on the expression, structure, biophysical properties, function, polymorphisms, and regulation of TRPV6. The aberrant expression, polymorphisms, and dysfunction of this protein linked to human diseases are also discussed.

Bioactive Compounds and Pharmacological Potential of Pomegranate (Punica granatum) Seeds - A Review

The use of complementary medicine has recently increased in an attempt to find effective alternative therapies that reduce the adverse effects of drugs. Pomegranate (Punica granatum L.) by-products, such as seeds, is a rich source of phytochemicals with a high antioxidant activity, thus possessing health benefits. For the identification and quantification of the pomegranate seeds chemical compounds, particular attention has been drawn to the latest developments in the HPLC coupling with electrospray ionization (ESI) MS/MS detection. In fact, a wide range of phytochemicals including phenolic acid, anthocyanins, flavonoids, hydrolysable tannins and other polyphenols were characterized. Furthermore, an exhaustive review of the scientific literature on pomegranate seeds on biomedicine and pharmacotherapy was carried out. Indeed, both in vitro and in vivo studies have demonstrated how pomegranate seeds possess antioxidant, anti- cardiovascular diseases, anti-osteoporosis, antidiabetic, anti-inflammatory and anticancer activities. The present review describes a recent tendency in research focusing on the chemical and biomedical features of the pomegranate seeds to value them as natural additives or active compounds for first-order diseases.

Intestinal Ca2+ absorption revisited: A molecular and clinical approach

Ca2+ has an important role in the maintenance of the skeleton and is involved in the main physiological processes. Its homeostasis is controlled by the intestine, kidney, bone and parathyroid glands. The intestinal Ca2+ absorption occurs mainly via the paracellular and the transcellular pathways. The proteins involved in both ways are regulated by calcitriol and other hormones as well as dietary factors. Fibroblast growth factor 23 (FGF-23) is a strong antagonist of vitamin D action. Part of the intestinal Ca2+ movement seems to be vitamin D independent. Intestinal Ca2+ absorption changes according to different physiological conditions. It is promoted under high Ca2+ demands such as growth, pregnancy, lactation, dietary Ca2+ deficiency and high physical activity. In contrast, the intestinal Ca2+ transport decreases with aging. Oxidative stress inhibits the intestinal Ca2+ absorption whereas the antioxidants counteract the effects of prooxidants leading to the normalization of this physiological process. Several pathologies such as celiac disease, inflammatory bowel diseases, Turner syndrome and others occur with inhibition of intestinal Ca2+ absorption, some hypercalciurias show Ca2+ hyperabsorption, most of these alterations are related to the vitamin D endocrine system. Further research work should be accomplished in order not only to know more molecular details but also to detect possible therapeutic targets to ameliorate or avoid the consequences of altered intestinal Ca2+ absorption.

Cardiovascular risk assessment in osteoporotic patients using osteoprotegerin as a reliable predictive biochemical marker

Osteoprotegerin (OPG), a member of the tumour necrosis factor receptor (TNFR) superfamily of proteins known to be involved in a large number of biological systems, plays a pivotal role in bone remodelling. In addition to the roles of OPG in bone metabolism, it has been reported to be associated with a high cardiovascular risk in patients with metabolic syndrome. In most cases, the exact functions of OPG remain to be established; however, the widespread expression of OPG suggests that this molecule may have multiple biological activities, mainly in the cardiometabolic environment. The aim of this study was to evaluate the value of OPG as a predictive marker for cardiovascular and metabolic risk in osteoporotic patients. The study group comprised patients with osteoporosis, in order to evaluate the association between OPG serum levels and cardiovascular pathology. Our results revealed significant correlations between classical biochemical bone and metabolic parameters, such as osteocalcin and parathyroid hormone with lipid and glucose biomarkers, sustaining the crosstalk between calcium and bone parameters and cardiovascular risk. The OPG serum level proved to have a significant and independent predictive value for metabolic syndrome (MetS) as a cardiovascular risk standard in osteoporotic patients. The OPG serum levels were increased in patients with MetS as a protective response against the atherosclerotic lesions. The serum levels of 25-hydroxy vitamin D had significant and independent predictive value for cardiovascular and metabolic risk in our subjects, sustaining the active role of vitamin D beyond the area of bone metabolism.