Study On Chemical Constituents And Anti-inflammatory Activity Of Picrasma Quassioides

Picrasma quassioides belonged to the genus Picrasma（family Simaroubaceae）,is mainly distributed in southern provinces of China.The whole plant has the effects of clearing heat,clearing dampness and detoxification,and can be used for wind-heat flu,sore throat,diarrhea,eczema,sores,snake bites and other symptoms.Modern scientific research has found that P.quassioides mainly contains various chemical components such as quassinoids,alkaloids,triterpenoids and volatile oils.Many of these compounds are known to have antibacterial,anti-inflammatory,anti-cancer and anti-hypertensive activities.In this paper,the dried stems of P.quassioides were refluxed with 95%ethanol to obtain an extract,and the extract was suspended in water and then extracted with ethyl acetate.The obtained ethyl acetate fraction was subjected to silica gel column chromatography,and various column chromatography techniques such as MCI,C₁₈ reverse phase column,Sephadex LH-20,and preparative HPLC were used to purify different fractions,and 43 compounds and two pairs of mixtures were isolated therefore.Based on modern spectroscopy（HR-ESI-MS,1D-NMR,2D-NMR）,these compounds were identified as kumulactone F（1）,kumulactone G（2）,α-andβ-picrasinoside L（3）,kumulactone H（4）,kumulactone I（5）,kumulactone J（6）,kumulactone K（7）,kumulactone C（8）,picrasin D（9）,picraqualide D（10）,quassin（11）,12-norquassin acetate（12）,12-norquassin（13）,picrasin B（14）,picraqualide B（15）,kusulactone（16）,nigakilactone A（17）,nigakilactone E（18）,nigakilactone C（19）,nigakilactone F（20）,nigakilactone B（21）,picrasin A（22）,α-andβ-neoquassin（23）,4（15）-eudesmene-1β,6α-diol（24）,carainterol A（25）,10α-hydroxycadin-4-en-15-al（26）,canangaterpene III（27）,10β-hydroxyiso-dauc-6-en-14-al（28）,（+）-aphanamol I（29）,1-carbomethoxy-β-carboline（30）,1-formyl-4-methoxy-β-carboline（31）,1H-Indole-3-carbaldehyde（32）,（-）-syringaresinol（33）,pinoresinol（34）,（+）-medioresinol（35）,magnolianone（36）,erythro-2,3-bis（4-hydroxy-3-methoxyphenyl）-3-ethoxypropan-l-ol（37）,coniferyl alcohol（38）,pandanusphenol B（39）,ethyl 3,4-dihydroxy-5-methoxybenzoate（40）,sinapaldehyde（41）,4-hydroxybenzaldehyde（42）,3,4,5-trimethoxyphenol（43）,scopoletin（44）,4-hydroxy-2,3-dimethyl-2-nonen-4-olide（45）.Among of these compounds,compounds 1,2,4,5,6,7 are new compounds,3 is a pair of undescribed epimer.The inhibitory activity of the quassinoids 1-23 and the three alkaloids 30-32 isolated from the P.quassioides against LPS-activated microglia was measured,and it was found that the compounds 30 and 31 have strong inhibitory activity,with IC₅₀ values of 2.34 and 0.35μM,and the remaining compounds showed no significant inhibitory activity(IC₅₀>50μM).