LAUSR

Rhodiola species are flowering perennial plants in Crassulaceae family that have been used in folk medicine in Asia and Europe for thousands of years. In traditional Chinese medicine, Rhodiola species was initially documented in Sheng Nong’s herbal classic, the earliest known compendium of Chinese Materia Medica compiled 2000 years ago, as a top grade herb with the capacity to promote healthy ageing and longevity.1 Rhodiala species commonly refer to “golden root” or “arctic root”, presumably because this indigenous plant from the arctic region has been believed to own marked health-boosting effects and part of the plant used in traditional medicine is rhizome or underground stem. Recent studies show that Rhodiola species have a broad spectrum of pharmacological activities and therapeutic effects, including antioxidant, adaptogenic, anti-stress, antimicrobial, immunomodulatory and antitumor effects.2 The extracts of Rhodiola species are available worldwide as a dietary supplement, and purportedly have many beneficial effects, such as improvement of cognitive function, reduction of mental fatigue, stress relief, enhancement of endurance and exercise performance.3 Constituting roughly 1% of raw herb, salidroside (Sal, a glucoside of tyrosol) was identified as a major biologically active component of Rhodiola species.2 The pharmacological activities of Sal, including its anti-inflammatory effect, have been extensively studied. For example, Wang et al. reported that Sal markedly inhibits the level of proinflammatory cytokines and airway inflammation in asthma induced by diisocyanate (TDI) in mice by regulating GATA3/T-bet.4 Recently, the antiarthritis activities of Sal were convincingly studied by Liu and colleagues, which further advances our understanding of its anti-inflammatory property and the underlying mechanism of action of this ancient golden root-derived compound.5 In this study, Liu and colleagues examined the effect of Sal on inflammatory response in a rat model of gouty arthritis induced by treatment with monosodium urate (MSU) crystals.5 It is well-known that macrophages play a central role in pathogenesis of gouty arthritis. After deposition of MSU crystals in the synovial membrane to form the gouty tophus, resident tissue macrophages are activated and high levels of proinflammatory cytokines are produced in the joints, which results in bone erosion.6 Furthermore, during the progression of MSU crystal-induced gouty arthritis, infiltrating monocytes differentiate intoM1-type hyperinflammatorymacrophages, which exacerbates inflammation during a gouty attack.7 Liu and colleagues thus focused on the study of the effect of Sal on the function of macrophages. They found that treatment with Sal potently inhibited the expression