Effect of Black Tea Extract and Thearubigins on Osteoporosis in Rats and Osteoclast Formation in vitro

Abstract

Background: Osteoporosis is a major health problem that is closely related to substantial morbidity, mortality and decline in life quality for the aging population. Although previous studies and epidemiological evidence have demonstrated an association between black tea consumption and the prevention of bone loss, the underlying mechanism remains unclear. So, the effect of black tea extract (BTE) and thearubigins (TRs) on osteoporosis in rats and osteoclast formation in vitro were investigated.Methods: In vivo, ovariectomized (OVX) rats were used to establish osteoporosis models. To validate the model and study the effects of BTE and TRs on osteoporosis, the female Wistar rats were divided into a sham-operated group and five OVX groups including model, Xian-Ling-Gu-Bao (XLGB) (as a positive control), BTE, TRs low-dose, and TRs high-dose group. The rats in the four treatment groups were given the corresponding test sample for 12 weeks. Then, the body weight, femur indices, and serum biomarkers were examined and analyzed. In vitro, RAW264.7 murine macrophages were used as model of osteoclast formation. The effects of BTE and TRs on osteoclasts formation and the specific genes and protein levels of osteoclasts were determined.Results: Although there was no significant effect on the OVX-induced body weight gain by BTE or TRs, the levels of maximum bending force, cortical bone thickness and biomarker of bone resorption (acid phosphatase) can be significantly ameliorated by BTE or TRs in OVX rats. Furthermore, both of BTE and TRs can inhibit the osteoclastogenesis and diminish the expression levels of the related genes and proteins.

Red Rooibos Tea Stimulates Osteoblast Mineralization in a Dose-Dependent Manner

“…To better understand the direct effects of both "true teas" and herbals on bone formation and resorption, osteoblast, and osteoclast cell models have also been used. In both osteoblast and osteoclast models, cells supplemented with black or green tea or specific polyphenols present in these teas have consistently shown positive effects as measured by increased mineral formation [30][31][32] and reduced bone resorption [33,34]. Previously, two different concentrations of green rooibos tea (1 and 10 µg/mL of polyphenols) had been tested in an osteoblast cell model [32].…”

Purple tea water extract blocks RANKL-induced osteoclastogenesis through modulation of Akt/GSK3β and Blimp1-Irf8 pathways

“…Previous studies have demonstrated that tea decoctions and extracts can therapeutically alleviate osteolytic bone loss. 12,13 Although purple tea (Zijuan tea) extracts shown to possess many health benefits, such as anti-inflammatory, anti-proliferative, and anti-oxidative stress characteristics, 14,28 its effects on osteoclast formation have not yet been reported. In this study, we demonstrated that a water-based extract of purple tea could effectively inhibit RANKL-induced osteoclastogenesis in vitro while also reducing bone degradation in vivo in LPS-treated mice.…”

“…10 Due to their rich antioxidant components, tea-based beverages exhibit enormous salutary properties for improving human health, as demonstrated in numerous previously reported investigations of anti-osteolytic properties of green tea or black tea extracts. [11][12][13] Purple tea, also known as Zijuan tea (Camellia sinensis var. kitamura), is known for its purple leaves, stems, and buds and abundant nutrients and beneficial components, such as anthocyanins, polyphenols, zinc, caffeine, and many others.…”

Black and Green Tea as Well as Specialty Teas Increase Osteoblast Mineralization with Varying Effectiveness

“…The effects of tea and its specific polyphenols on both osteoblasts and osteoclasts have been studied using cell models. [11][12][13][14][15][16][17][18][19] The majority of studies using osteoblasts have studied the effects of green or black teas and have consistently shown increases in mineralization in response to tea. More specifically black, green, and rooibos (red and green) teas have been shown to increase mineralization at concentrations likely attainable through diet.…”

“…[14][15][16] While studies in osteoclasts are limited, previously published studies have shown that black, green, or green rooibos teas elicit a decrease in activity. [17][18][19] The majority of literature has investigated green and black teas. Based on current trends of tea consumption in the Canadian market, information regarding the influence of specialty teas on health, including bone health, may further increase interest among consumers.…”