Dracocephalum kotschyi Boiss. has been used as part of an ethnobotanical remedy against many forms of human cancer in Iran. It has been demonstrated that a flavonoid named xanthomicrol from D. kotschyi contributes to its preferential antiproliferative activity against malignant cells. In the present study, the antiproliferative activity of its flavonoid fraction was further characterized. Using liquid-liquid extraction and a semi-preparative reversed-phase HPLC method, eight flavonoid aglycones were isolated from the aerial parts of the plant and their identities were confirmed through MS and NMR analyses as luteolin, naringenin, apigenin, isokaempferide, cirsimaritin, penduletin, xanthomicrol and calycopterin. The in vitro antiproliferative activity of each compound was evaluated against a panel of established normal and malignant cell lines using the MTT assay and some structure-activity relationships were observed. The hydroxyflavones (luteolin, apigenin and isokaempferide) exerted comparable antiproliferative activities against malignant and normal cells, while the methoxylated hydroxyflavones (cirsimaritin, penduletin, xanthomicrol and calycopterin) showed preferential activities against tumor cells. This activity may be of value in treating tumors as it would exert few side effects in normal tissues. Xanthomicrol selectively inhibited the growth of human gastric adenocarcinoma, while calycopterin selectively prevented human acute promyelocytic leukemia and human colon carcinoma cells proliferation.
A molecularly imprinted polymer (MIP) against lamotrigine (LTG) was prepared, characterized, and its recognition properties were compared with a blank nonimprinted polymer (NIP). Two classes of binding sites were found in the MIP--high affinity (K(D) = 16.2 microM) and low affinity (K(D) = 161.3 microM). Selectivity of the synthesized MIP was examined using compounds with similar structures or therapeutic uses to LTG. In compounds which had structural similarity to LTG, the presence of amine groups appeared to affect binding to the MIP, however overall shape of the molecule was also important. Under the optimal conditions developed, other anticonvulsant drugs tested did not bind the MIP. A molecularly imprinted SPE (MISPE) procedure was developed which had a recovery of 84-89%, interday variation of less than 3.4% and intraday variation of less than 2.8%. The MISPE procedure was compared with a routine liquid-liquid extraction (LLE) procedure used for the HPLC determination of LTG in serum from patients. The data indicated that the MIP synthesized showed both good selectivity and high affinity for LTG and could be used for the extraction of the drug from serum samples or as the receptor layer for an LTG selective biosensor.
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