Piper longum fruit extract. The fruit contains 1% volatile oil, resin, alkaloids Piperin and piperlonguminine, a waxy alkaloid N-isobutyl deca-trans-2-trans-4-dienamide and a terpenoid substance. The roots have piperine, periongumine or piplartin, dihydro-stigmasterol, which have been the reason that it is popularly used in traditional practice to promote respiratory health. In a few weeks-clinical study with 20 children Piper longum extract significantly benefited respiratory function. It has been known to effectively reduce passive cutaneous anaphylaxis in rats and proteacted guinea pigs against antigen induced bronchospasm. (Dahanukar.S et.al.Indian Drugs 19:271(1982). Major chemical constituents: Essential oil. Mono and sesquiterpenes, caryophyllene (mainly), Piperine, Piperlongumine, Piperlonguminine, Pipernonaline, Piperundecalidine, Pipercide, Sesamin, B- sitosterol four aristolactams (cepharanone B. aristolactum All. Piperlactum A and  piperolactam B) five 4-5 dioxoaporphines etc. The essential oil of the fruit P. longum is a complex mixture, the three major components of which are (excluding the volatile piperine) caryophyllene and pentadecane (both about 17.8%) and bisaboline (11%). Others include thujine, terpinoline, zingiberine, pcymene, p-methoxy acetophenone and dihydrocarveol. Long pepper contains less essential oil than its relatives (about 1%), which consists of sesquiterpene hydrocarbons and ethers (bisabolene, β-caryophyllene, β-caryophyllene oxide, each 10 to 20%; α-zingiberene, 5%), and saturated aliphatic hydrocarbons such as 18% pentadecane, 7% tridecane, 6% heptadecane. The essential oil of the fruits showed fungicidal activity of P. longum L. The fruit-derived materials was tested towards six phytopathogenic fungi, Pyricularia oryzae, Rhizoctonia solani, Botrytis cineria, Phytophthora infestans, Puccinia recondita, and Erysiphe graminis using a whole plant in vivo method 42-44. A piperidine alkaloid, pipernonaline, was isolated from the hexane fraction of P.longum showed a potent fungicidal activity against P. recondita with 91% and 80% control values at the concentration of 0.5 and 0.25 mg ml−1.

Source: Dweck, Anthony. Handbook of Natural Ingredients (Dweck Books 4) . Dweck Data.