Java Tea (Orthosiphon stamineus) protected against osteoarthritis by mitigating inflammation and cartilage degradation: a preclinical study.

The effect of Orthosiphon stamineus aqueous (OSA) extract against osteoarthritis (OA) was investigated in explant cartilage culture and in postmenopausal OA rat model. Female rats were bilaterally ovariectomized (OVX). Osteoarthritis was induced after surgical recovery, by intra-articular injection of monosodium iodoacetate (MIA) into the right knee. Rats were grouped (n = 8) into: healthy sham control; non-treated OA; OA + diclofenac (positive control 5 mg/kg); and two doses OSA (150-300 mg/kg). After 4 weeks' treatment, rats were evaluated for OA-related parameters and biomarkers. The OSA reduced proteoglycan and ROS release from the cartilage explants under inflammatory (IL-1b) conditions. In the OA-induced rats' cartilages, the OSA downregulated the mRNA expressions for IL-1ß, IL-6, IL-10, TNF-α, NF-κß, NOS2, PTGS2, PTGER2, ACAN, COL2A1, MMP1, MMP13, ADAMTS4, ADAMTS5 and TIMP1, mostly dose-dependently. The OSA reduced the OA rats' serum levels for PGE2, CTX-II, TNF-α, MMP1, MMP13, PIINP, OPG, RANKL, OC and BALP, but not dose-dependently. The OSA contained polyphenols and flavonoids (tetramethoxyflavone). The OSA alleviated articular cartilage degradation, inflammation, collagenase/aggrecanase activities, to improve joint and subchondral bone structure. O. stamineus mitigated osteoarthritis by downregulating inflammation, peptidases and aggrecanases, at a dose equivalent to about 30 mg/kg for humans.

Orthosiphon stamineus (Misai Kucing) ameliorated postmenopausal osteoporosis in rat model.

OBJECTIVE: Orthosiphon stamineus (OS) or Misai Kucing (Java tea) is a popular herbal supplement from Southeast Asia for various metabolic, age-related diseases. This study investigated the potential use of OS leaf extracts to ameliorate osteoporosis in ovariectomized rats. METHODS: Fifty-six female Sprague-Dawley rats were randomly allocated into eight groups (n = 7): SHAM (healthy sham control); OVX (ovarietomized) nontreated rats (negative control); OVX + Remifemin (100 mg/kg body weight), and 2% green tea extract (positive controls); OVX + OS 50% ethanolic and aqueous extracts, both at either 150 or 300 mg/kg. After 16 weeks, the rats' bones and blood were evaluated for osteoporosis indicators (protein and mRNA expressions), micro-computed tomography for bone histomorphometry, and three-point bending test for tibia mechanical strength. RESULTS: The extracts dose-dependently and significantly (P < 0.05) improved bone strength and flexibility, bone mineral density, bone formation protein markers (P1NP), and bone histomorphometry. All extracts reduced the inflammation biomarker (interleukin-6). The extracts up-regulated osteoblastogenesis (bone morphogenetic protein-2) and collagen-1 synthesis (collagen type 1 alpha-1) mRNA expressions, and down-regulated bone resorption (TNFSF11 and nuclear factor-kappa B) mRNA expressions. Both the water and 50% ethanolic extract were effective. The effective dose is equivalent to 25 to 50 mg/kg extract for humans. CONCLUSIONS: The extract showed bone-protective and antiosteoporotic effects (improving bone strength, flexibility, bone density, and bone morphometry) by reducing inflammation and the bone resorption biomarkers, while enhancing bone formation biomarkers and collagen synthesis.