Immune modulatory effect of a novel 4,5-dihydroxy-3,3´,4´-trimethoxybibenzyl from Dendrobium lindleyi.

Dendrobium bibenzyls and phenanthrenes such as chrysotoxine, cypripedin, gigantol and moscatilin have been reported to show promising inhibitory effects on lung cancer growth and metastasis in ex vivo human cell line models, suggesting their potential for clinical application in patients with lung cancer. However, it remains to be determined whether these therapeutic effects can be also seen in primary human cells and/or in vivo. In this study, we comparatively investigated the immune modulatory effects of bibenzyls and phenanthrenes, including a novel Dendrobium bibenzyl derivative, in primary human monocytes. All compounds were isolated and purified from a Thai orchid Dendrobium lindleyi Steud, a new source of therapeutic compounds with promising potential of tissue culture production. We detected increased frequencies of TNF- and IL-6-expressing monocytes after treatment with gigantol and cypripedin, whereas chrysotoxine and moscatilin did not alter the expression of these cytokines in monocytes. Interestingly, the new 4,5-dihydroxy-3,3',4'-trimethoxybibenzyl derivative showed dose-dependent immune modulatory effects in lipopolysaccharide (LPS)-treated CD14lo and CD14hi monocytes. Together, our findings show immune modulatory effects of the new bibenzyl derivative from Dendrobium lindleyi on different monocyte sub-populations. However, therapeutic consequences of these different monocyte populations on human diseases including cancer remain to be investigated.

A Recombinant Fab Antibody Against Kwakhurin as a Tool for Sensitive Indirect Competitive ELISA.

BACKGROUND: Pueraria candollei var. mirifica (P. candollei), known as White Kwao Krua in Thai, has long been used in traditional Thai medicine for the symptoms of menopause due to the potent estrogenic activity exhibited by the isoflavonoids and chromenes it contains. Recently, health hazards caused by P. candollei-derived products have arisen in Japan, and demands for analytical methods to standardize the P. candollei have been increasing. Previously, we have focused on quantifying the unique P. candollei-derived isoflavonoid kwakhurin (Kwa) and developed an indirect competitive enzyme- linked immunosorbent assay (icELISA) using a monoclonal antibody (MAb) against Kwa. However, MAb preparation requires the use of costly culture medium and sophisticated techniques. OBJECTIVE AND METHOD: In this study, we produced a recombinant antigen-binding fragment (Fab) against Kwa, as an alternative to MAb, for use in icELISA for quantitative analysis of Kwa. The VHCH1 and VL-CL proteins were individually expressed in Escherichia coli BL21 (DE3) strain and were then refolded to form active anti-Kwa Fab. RESULTS AND CONCLUSION: Characterization of anti-Kwa Fab revealed that it possessed high specificity (cross-reactivities with other Kwa-related compounds, <0.03%) and high sensitivity (limit of detection, 8.16 ng/mL). Additionally, validation analyses indicated that icELISA using anti-Kwa Fab is highly precise, accurate, and sufficiently reliable for use in quantitative analysis of Kwa. Consequently, an icELISA incorporating anti-Kwa Fab was developed for the analysis of P. candollei-derived products, to assure consumer safety.