The Study On The Chemical Constituents Of The Roots Of Piper Nigrum Linn.

Piper nigrum Linn. (Piperaceae) is widely distributed in the tropical and subtropical regions of the world. Pepper (fruits of P. nigrum) is one of the most popular spices in the world and has been also used as a folk medicine due to its many physiological activities, e.g. stimulation of the central nervous system, analgesic, and antipyretic activities. The fruit of P. nigrum has been extensively investigated for its chemical constituents and revealed that amide alkaloids were the main constituents. However, its root was very little known except that local people in Hainan use it as not only spice but also improving sleep.By means of silica gel, opening ODS and HPLC, 60 amide alkaloids were isolated from the roots of P. nigrum, and their structures were elucidated on the basis of spectroscopic data and chemical methods. The compounds were comprised of 39 monomeric amide alkaloids including 7 new compounds, 16 novel cyclohexene-type dimeric amide alkaloids including 15 new compounds, and 5 cyclobutane-tpye dimeric amide alkaloids including 4 new compounds. The 26 new compounds were named as N-isobutyl-4-hexanoyl-4-hydroxypyrrolidin-1-one (1), (±)-erythro-1-(1-oxo-4,5-dihydroxy-2E-decaenyl)-piperidine (2), (±)-threo-1-(1-oxo-4,5-dihydroxy-2E-decaenyl)-piperidine (3), (±)-threo-N-isobutyl-4,5-dihydroxy-2E-octaenamide (4), 1-(1,6-dioxo-2E,4E-decadienyl)-piperidine (5), 1-[1-oxo-3(3,4-methylenedioxy-5-meth-oxyphenyl)-2Z-propenyl]-piperidine (6), 1 -[ 1 -oxo-5(3,4-methylenedioxyphenyl)-2Z,4E-pent-adienyl]-pyrrolidine (7), nigramides A (40), nigramides B (41), nigramides C (42), nigramides D (43), nigramides E (44), nigramides F (45), nigramides G (46), nigramides H (47), nigramides I (48), nigramides J (49), nigramides K (50), nigramides L (51), nigramides M (52), nigramides N (53), nigramides O (54), nigramides P (56), nigramides Q (57), nigramides R (58), nigramides S (59). Together with 34 known compound: 1-[1-oxo-3-phenyl-2E-propenyl]-piperidine(8), 1-[1-oxo-3(3,4-methylenedioxyphenyl)-pro-pan]-piperidine (9), 1-[1-oxo-3(3,4-methylenedioxyphenyl)-2E-propenyl]-piperidine (10),...