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Comparison of Different Tea Types on Osteoblast Activity
Author(s) -
Nash Leslie,
Ward Wendy
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.924.34
Subject(s) - polyphenol , chemistry , gallic acid , osteoblast , food science , black tea , ethanol , biochemistry , antioxidant , in vitro
Many studies report that tea consumption is associated with higher bone mineral density in women. Polyphenols in tea may mediate such benefits. We examined if English Breakfast (EB) and Golden Monkey (GM) black tea, green tea (GT) or rooibos tea (RT) increased osteoblast activity in human osteoblast‐like cells. Preclinical studies typically use alcohol‐derived polyphenol extracts although tea for human consumption is prepared with water. We determined that polyphenol levels are higher with methanol versus water extraction (161 mg/g vs. 86 mg/g gallic acid equivalents, p < 0.001). Water extraction reduced polyphenol levels of GT, EB, and GM by more than 50%, whereas RT maintained 65% of its polyphenols. GT (117‐235 mg/g) and EB (121‐202 mg/g) had the highest polyphenol content, regardless of solvent (p < 0.001). For mineralization, the effect of water‐extracted polyphenols (1 or 10 µg polyphenols/mL media) were measured using the Alizarin Red assay. Cellular activity was examined by reduction of thiazolyl blue tetrazolium bromide (MTT). Two‐way ANOVA indicated a favorable effect of dose (1 or 10 µg/mL, p<0.001) and treatment (p < 0.001) on mineralization. 10 µg/mL tea extract produced less mineral than 1 µg/mL (132% vs. 157% of control, p < 0.001). Both doses of GT (p < 0.001, p < 0.001) and RT (p < 0.05, p < 0.01), but only 1 µg/mL of EB (p < 0.001) and GM (p < 0.001) increased mineralization. Both doses of GT (p < 0.05, p < 0.05) and RT (p < 0.001, p < 0.01) and 1 µg/mL of EB (p < 0.05) promoted greater cellular activity at 24 hrs. Neither dose of GM, nor 10 µg/mL of EB resulted in significant differences of MTT. Differing effects among tea types may be due to diverse polyphenol profiles. (Funded by NSERC Discovery Grant)