OBJECTIVE: This review systematically summarised the therapeutic effects of PS on preventing osteoporosis and promoting fracture healing.
METHODS: A systematic literature search was performed in November 2021 using 4 electronic databases and the search string "Piper sarmentosum" AND (bone OR osteoporosis OR osteoblasts OR osteoclasts OR osteocytes).
RESULTS: Nine unique articles were identified from the literature. The efficacy of PS has been studied in animal models of osteoporosis induced by ovariectomy and glucocorticoids, as well as bone fracture models. PS prevented deterioration of bone histomorphometric indices, improved fracture healing and restored the biomechanical properties of healed bone in ovariectomised rats. PS also prevented osteoblast/osteocyte apoptosis, increased bone formation and mineralisation and subsequently improved trabecular bone microstructures and strength of rats with osteoporosis induced by glucocorticoids. Apart from its antioxidant and anti-inflammatory activity, PS also suppressed circulating and skeletal expression of corticosterone and skeletal expression of 11β hydroxysteroid dehydrogenase type 1 but increased the enzyme activity in the glucocorticoid osteoporosis model. This review also identified several research gaps about the skeletal effects of PS and suggested future studies to bridge these gaps.
CONCLUSION: PS may be of therapeutic benefit to bone health. However, further research is required to validate this claim.
SUMMARY: This review assesses the accumulated evidences on the mutual influence of monoamines, hormones and neuropeptides that are linked to obesity. A few anti-obesity drugs that exert their mechanisms of action through monoamines are briefly discussed to support the notion of monoamines being a critical target of drug discovery for new anti-obesity drugs. Subsequently, the review provides a comprehensive overview of central dopamine and serotonin changes that are associated with the use of khat or its alkaloids. Then, all the studies on khat that describe physical, biochemical and hormonal changes are summarised and discussed in depth.
CONCLUSION: The reviewed studies provide relatively acceptable evidence that different khat extracts or cathinone produces changes in terms of weight, fat mass, appetite, lipid biochemistry and hormonal levels. These changes are more pronounced at higher doses and long durations of intervention. The most suggested mechanism of these changes is the central action that produces changes in the physiology of dopamine and serotonin. Nonetheless, there are a number of variations in the study design, including species, doses and durations of intervention, which makes it difficult to arrive at a final conclusion about khat regarding obesity, and further studies are necessary in the future to overcome these limitations.