Two new phragmalin-type limonoids orthoesters from Entandrophragma candollei / 中国天然药物

Two new phragmalin-type limonoids orthoesters, encandollens A and B (1 and 2), were isolated from the stem barks of Entandrophragma candollei collected in Ghana. The structures of these compounds were elucidated on the basis of HR-ESI-MS, H and C NMR, HSQC, HMBC, and ROESY data. Compound 1 was a rare C-15 enolic acyl phragmalin-type limonoid orthoester. Compounds 1 and 2 exhibited weak inhibitory effects on NO production in lipopolysaccharide (LPS)-induced RAW 264.7 cells.

A comparative evaluation of in vivo antiplasmodial activity of aqueous leaf exracts of Carica papaya, Azadirachta indica, Magnifera indica and the combination thereof using plasmodium infected BALB/c mice.

Combination of herbal plants may produce synergistic, additive or antagonistic effects. A concoction prepared from the aqueous leaf extracts of Azadirachta indica (ALEAI), Magnifera indica (ALEMI), Carica papaya (ALECP) has been used in the treatment of malaria in some parts of Ghana. In the present study, ALEAI, ALEMI, ALECP and their combination (AMC) were evaluated in vivo for antiplasmodial activities using Plasmodium berghei infected BALB/c mice. Freeze-dried extracts of the combined therapy as well as those of the individual plants were tested in vivo on Plasmodium berghei infected BALB/c mice at 50 mg/kg and 100 mg/kg dosages. Coartem at 20 mg/kg and water were used as positive and negative controls respectively. Cryptolepsis sanquinolata was also used as a positive control. The extracts showed varying antiplasmodial activities using Four day suppressive and Seven day repository tests. The antiplasmodial activities of the extracts were significant compared with the negative control (P<0.05). Exceptions were ALECP at 50 mg/kg (3.98%) and the combined therapy (AMC) at 100 mg/kg (4.36%) which were only significant in the repository test. Although the combined therapy at 50 mg/kg showed the highest chemo-suppression (54.07%) when compared with the individual test extracts (ALECP = 19.13%; ALEMI = 51.81% and ALEAI = 48.95%) at similar dose, the activity was neither a demonstration of synergistic nor additive effect. These results suggest that the active components in the various single plant extracts may overlap in their modes of action. At dose 100 mg/kg, the AMC showed the least chemo-suppression suggesting an increased amount of a possible antagonistic component. Phytochemical screening of the various aqueous extracts revealed the presence of bioactive compounds with reported antiplasmodial properties. The LD50 recorded for the various extracts was greater than 5000 mg/kg. In conclusion, ALEAI, ALEMI, ALECP and their combination (AMC) possess antiplasmodial properties and this supports their use in folkloric medical setting in treating malaria.