Determination of flavonoids from Orthosiphon stamineus in plasma using a simple HPLC method with ultraviolet detection

In vitro and in vivo structure and activity relationship analysis of polymethoxylated flavonoids: Identifying sinensetin as a novel antiangiogenesis agent

“…For example, the peel of shaddock ( Citrus maxima ) and the peel of mature citrus ( Pericarpium Citri Reticulatae ) are commonly used as food and tea in China. It has been shown that the maximum concentrations of sinensetin and nobiletin in rat plasma after oral administration of 10 g/kg of Orthosiphon stamineus extract (equivalent to 15 mg/kg of sinensetin) and 50 mg/kg of nobiletin were about 0.1 μg/mL and 1.78 μg/mL, respectively []. The bioavailabilities of sinensetin and nobiletin, 9.4 and 10%, respectively, are relatively high when compared with that of (—)‐epigallocatechin‐3‐gallate (EGCG) (0.1% in rat), which is the principal active polyphenol in green [].…”

“…It has been shown that the maximum concentrations of sinensetin and nobiletin in rat plasma after oral administration of 10 g/kg of Orthosiphon stamineus extract (equivalent to 15 mg/kg of sinensetin) and 50 mg/kg of nobiletin were about 0.1 μg/mL and 1.78 μg/mL, respectively []. The bioavailabilities of sinensetin and nobiletin, 9.4 and 10%, respectively, are relatively high when compared with that of (—)‐epigallocatechin‐3‐gallate (EGCG) (0.1% in rat), which is the principal active polyphenol in green []. In several epidemiological studies, it was shown that the consumption of five cups of green tea per day could lower the risks of breast, liver, and/or lung cancers [].…”

Toxicity evaluation of a standardised 50% ethanol extract of Orthosiphon stamineus

“…stamineus leaves have been widely used for the treatment of many ailments. Many studies have demonstrated their utility, including their biological activities, in vitro (Akowuah et al, 2004;Awale et al, 2003;Olah et al, 2003) and their therapeutic benefits in rodents (Loon et al, 2005;Schut and Zwaving, 1993). In a study by Han et al, rats were administered different doses (5, 50 or 500 mg/kg/day) of a crude methanol extract of O. stamineus leaves for a period of 14 days.…”

Evaluation of the genotoxicity of Orthosiphon stamineus aqueous extract

“…The unchanged rosmarinic acid is rapidly absorbed after oral administration reaching maximum concentrations (C max ) within 30 min in the human peripheral blood plasma (Baba et al, 2005). The oral bioavailability of some flavonoids (sinensetin, eupatorin and 3 -hydroxy-5,6,7,4 -tetramethoxyflavone) seems to be low (Loon et al, 2005). It should be noted, however, that the aforementioned kinetic data were obtained after the administration of rosmarinic acid alone, and that its absorption and metabolism by gut microflora can be eventually altered by the other constituents of the Orthosiphon stamineus extract.…”