ABSTRACT
The chemical constituents of the roots, seeds, and bark of Azadirachta indica var. siamensis were investigated, leading to the isolation of six tricyclic diterpenoids and five limonoids, including two new compounds (2, 5). The structures were elucidated based on NMR spectroscopic techniques, mass spectrometry and single-crystal X-ray diffraction as well as comparison with the literature. Moreover, the cytotoxicity activities of the isolates were evaluated. The results indicated that the compounds 1-3, 5-9 exhibited cytotoxicities against one or more cancer cell lines tested, with IC50 values in the range of 1.7-88.1 µM. The mechanism of action studies indicated that the most active compound, compound 5, could induce the apoptosis of AZ521 cells. Furthermore, the Western blot analysis showed that compound 5 could reduce the expression levels of procaspases-3, -8, -9 and promote the expression of Bid and AIF.
Subject(s)
Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Azadirachta/chemistry , Diterpenes/chemistry , Diterpenes/pharmacology , Limonins/chemistry , Limonins/pharmacology , Antineoplastic Agents, Phytogenic/isolation & purification , Apoptosis/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Crystallography, X-Ray , Diterpenes/isolation & purification , Drug Screening Assays, Antitumor , Humans , Limonins/isolation & purification , Models, Molecular , Neoplasms/drug therapyABSTRACT
The chemical constituents of the roots and bark of Azadirachta indica were investigated, leading to the isolation of six tricyclic diterpenoids and four limonoids including a new compound, azadirachtin J (4). The structures were elucidated on the basis of NMR spectroscopic techniques, mass spectrometry as well as comparison with the literature. Furthermore, melanogenesis-inhibitory activities of the isolated compounds were evaluated. As a result, compounds 1-3 and 10 exhibited superior inhibitory activities against melanogenesis with no, or almost no, toxicity to the cells (86.5-105.1% cell viability). Western blot analysis showed that compounds 1 and 3 exhibited melanogenesis inhibitory activities in α-MSH-stimulated B16 melanoma cells due to, at least in part, inhibition of the expression of MITF, followed by a decrease in the expression of tyrosinase, TRP-1, and TRP-2. Compounds 1 and 3 exhibited tyrosinase inhibitory activities (IC50 values of 44.86 µM and 69.85 µM respectively). Docking results confirm that the active inhibitors strongly interact with tyrosinase residues.
Subject(s)
Azadirachta/chemistry , Diterpenes/chemistry , Limonins/chemistry , Melanins/metabolism , Animals , Azadirachta/metabolism , Binding Sites , Cell Line, Tumor , Cell Survival/drug effects , Diterpenes/metabolism , Diterpenes/pharmacology , Limonins/metabolism , Limonins/pharmacology , Mice , Molecular Conformation , Molecular Docking Simulation , Monophenol Monooxygenase/antagonists & inhibitors , Monophenol Monooxygenase/metabolism , Plant Bark/chemistry , Plant Bark/metabolism , Plant Roots/chemistry , Plant Roots/metabolismABSTRACT
Chicoric acid is the main phenolic active ingredient in Echinacea purpurea (Asteraceae), best known for its immune-enhancing ability, as well as used as a herbal medicine. To achieve further utilization of medicinal ingredients from E. purpurea, an efficient preparative separation of chicoric acid was developed based on macroporous adsorption resin chromatography. The separation characteristics of several different typical macroporous adsorption resins were evaluated by adsorption/desorption column experiments, and HPD100 was revealed as the optimal one, which exhibited that the adsorbents fitted well to the pseudo-second-order kinetics model and Langmuir isotherm model, and the optimal process parameters were obtained. The breakthrough curves could be predicted and end-point could be determined early. Besides, the optimal elution conditions of chicoric acid can be achieved using the quality control methods. As a result, the purity of chicoric acid was increased 15.8-fold (from 4 to 63%) after the treatment with HPD100. The process of the enrichment and separation of chicoric acid is considerate, because of its high efficiency and simple operation. The established separation and purification method of chicoric acid is expected to be valuable for further utilization of E. purpurea according to product application in pharmaceutical fields in the future.
Subject(s)
Asteraceae/chemistry , Caffeic Acids/isolation & purification , Resins, Plant/chemistry , Succinates/isolation & purification , Adsorption , Caffeic Acids/chemistry , Molecular Structure , Particle Size , Porosity , Quality Control , Succinates/chemistry , Surface PropertiesABSTRACT
Three new C21 steroids, i.e., (3ß,17α,20S)-pregn-5(6)-ene-3, 17, 20-triol-3-O-ß-d-digitalopyranosyl-(1â¯ââ¯4)-ß-d-digitalopyranoside (4), (3ß,17α,20S)-pregn-5(6)-ene-3, 17, 20-triol-20-O-ß-d-glucopyranosyl-(1â¯ââ¯6)-ß-d-glucopyranosyl-(1â¯ââ¯2)-ß-d-digital-opyranoside (8), (3ß, 20R)-pregn-14(15)-ene-3, 20, 21-triol-3-O-ß-d-glucopy-ranoside (10), along with ten known C21 steroids were isolated from Streptocaulon juventas. Their structures were elucidated on the basis of 1D and 2D NMR spectroscopic techniques, mass spectrometry as well as comparison with the literature. All the isolated compounds were screened for their in vitro cytotoxicity against human liver cancer cells (HepG2) and the structure-activity relationships were also analyzed. Moreover, compounds 1-3, 5, 10-12, which displayed cytotoxic activities in HepG2 cells, were tested for the selective index (SI) by the ratio of cytotoxic effect on human hepatocytes (LO2) to that on HepG2. As a result, new compound 10 exhibited a good inhibitory activity against HepG2 with IC50 value 11.7⯵M as well as high SI value 3.5. Furthermore, compound 10 could induce HepG2 cells apoptosis by flow cytometry.
