Cervi cornu has been extensively used in traditional medicine as an antioxidant and for the treatment of various disorders, including osteoporosis. However, since it is not easy to separate the active ingredient, absorption is not performed well. In this study, we extracted the low molecular weight (843Da) collagen NP-2007 from cervi cornu by enzyme hydrolyzation, and evaluated the therapeutic effect in a monosodium iodoacetate (MIA)-induced rat osteoarthritis model, and identified their molecular mechanisms. NP-2007 was orally administered at 50, 100, and 200 mg/kg for 21 d. Efficacy was evaluated based on serum parameters, inflammatory mediators, and mor-phological and histopathological analyses of knee joints. Production of matrix metalloproteinases, including MMP-2, MMP-3, and MMP-9, in the serum was higher in MIA-treated rats; however, these levels decreased after NP-2007 treatment. Serum levels of tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and prostaglandin E2 were lower in the NP-2007 group than in the MIA group. Furthermore, the administration of NP-2007 resulted in effective preservation of both the synovial membrane and knee cartilage, and significantly decreased the transformation of fibrous tissue. This study indicates that NP-2007 can prevent and alleviate symptoms of osteoarthritis and have applications as a novel arthritis treatment.

The leaves of Ligustrum robustum have been applied as Ku-Ding-Cha, a functional tea to clear heat and remove toxins; and served as a folk medicine to deal with diabetes, obesity, and hypertension. Trans-p-hydroxycinnamic acid and its esters, which were isolated from the leaves of L. robustum, might be a new resource to prevent diabetes and its complications because of their strong -glucosidase and fatty acid synthase (FAS) inhibitory activities and antioxidant effect. However, the quantitative analytical method for trans-p-hydroxycinnamic acid and its esters in the leaves of L. robustum hasn’t been reported so far. In addition, it was difficult and troublesome to analyze no less than 34 trans-p-hydroxycinnamic acid esters by usual HPLC. Therefore, a new HPLC-UV method using hydrolyzation with sodium hydroxide for quantitation of trans-p-hydroxycinnamic acid and its esters in the leaves of L. robustum was developed in the present study. The optimal hydrolyzation conditions were as follows: 1 mL sodium hydroxide aqueous solution (1 M) was added into 1 mL the extract of L. robustum and incubated at 80 °C for 2 h , and then 1 mL hydrochloride (1 M) solution was added. HPLC analysis was performed in reverse phase mode using a C-18 column, eluting with methanol-0.1% acetic acid aqueous solution (40:60, v/v) in isocratic mode at a flow rate of 1.0 mL/min, and detecting at 310 nm. The analytical method was simple and rapid, which simplified greatly the analytical process. The method was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy. High linearity was demonstrated with correlation coefficient of 1.000 for trans-p-hydroxycinnamic acid. The LOD and LOQ values were 1.55 and 4.69 μg/mL, respectively. The relative standard deviations (RSD) of intra-day and inter-day variabilities for trans-p-hydroxycinnamic acid were less than 2%. The percentage recovery of trans-p-hydroxycinnamic acid was 101.2% ± 0.8%. Finally, the proposed method was applied successfully to the determination and comparison of the contents of trans-p-hydroxycinnamic acid and its esters in various extracts of the leaves of L. robustum. The 60%-70% ethanol extracts of L. robustum showed the highest contents of free trans-p-hydroxycinnamic acid (3.96-3.99 mg/g), and the 50%-80% ethanol extracts of L. robustum displayed the highest contents of trans-p-hydroxycinnamic acid esters (202.6-210.6 mg/g). The method can be applied also to the quality control of the products of L. robustum.