Two New Sesquiterpene Lactones from the Leaves of Laurus nobilis

Abstract

Laurus nobilis L. (Lauraceae) is an evergreen tree widespread in the Mediterranean area and Europe, and as a folk medicine, the decoction or tea of bay leaves is often used as a carminative, intestinal and gastric antispasmodic, against diarrhea, for rheumatic pains, in diseases of the respiratory tract, as a cough sedative, to treat asthma and cardiac diseases, [1][2][3] and in cases of dysmenorrhea (pers. comm.). Previous phytochemical investigations have led to the isolation of several classes of secondary metabolites of laurel leaves, particularly sesquiterpene lactones, 4,5) alkaloids, 5,6) monoterpene and germacrane alcohols, 5,7,8) catechin and procyanidine derivatives, 5,9) glycosylated flavonoids, 10) and megastigmane glucosides.11) As well as sesquiterpene lactones, laurenobiolide 12) and costunolide 13) have been identified as the major compounds of L. nobilis. Many of these lactone derivatives have been shown to possess various pharmacological effects, with antimicrobial, 14,15) immunomodulating 16) and cytotoxic activities. 17) Three costunolide and germacranolide derivatives, isolated from L. nobilis, were recently shown to be able to induce apoptotic chromatin condensation in leukemia cells (HL-60), 18,19) indicating their possibility as leads in the development of new classes of antileukemic drugs. For this reason, we considered this plant in our ongoing studies on antiproliferative agents from vegetal sources. Sequential extracts were prepared using solvents in increasing polarity (petroleum ether, chloroform and methanol), and residues were used to perform preliminary cytotoxic tests against two different cell lines. Activity against Jurkart cell line was established in petroleum ether (PEE) and chloroform extracts, with an IC 50 of 9.1 and 10.2 mg/ml respectively. Only PEE was active against LoVo with an IC 50 of 15.1 mg/ml. Fractionation of the extracts led to the isolation of five sesquiterpene lactones, two of which (1, 2) are new natural products.Compound 1 was obtained as colorless needles. The high resolution (HR)-MS [atmospheric pressure ionization-time of flight (API-TOF)] spectrum showed a protonated molecular ion [MϩH] ϩ at m/z 233.1524, corresponding to a molecular formula of C 15 H 20 O 2 . The IR spectrum showed the presence of a g-lactone ring (1765 cm As a part of our ongoing interest in new bioactive compounds from natural sources, we studied Laurus nobilis (Lauraceae). This plant is widespread in the Mediterranean area and is used for medicinal and economic purposes. Chromatographic separations on active extracts led to the isolation of two new sesquiterpene lactones, 5a,9-dimethyl-3-methylene-3,3a,4,5,5a,6,7,8-octahydro-1-oxacyclopenta[c]azulen-2-one (1) and 3b b-chlorodehydrocostuslactone (2). The structures of the new compounds were identified by 1D and 2D NMR experiments, as well as high resolution mass spectrometry. The cytotoxic activity was also evaluated against three different tumor cell lines of human origin.

Anti-methicillin Resistant Staphylococcus aureus (MRSA) Compounds Isolated from Laurus nobilis

“…Decoction or tea of leaves is often used as a carminative, an intestinal and gastric antispasmodic, an anti-diarrheal agent, for treating rheumatic pain, in treating diseases of the respiratory tract, as a cough sedative, and treating asthma and cardiac diseases. 14) This means that the laurel contains many medicinal compounds. It seems that C2 and C3 are two such medicinal compounds in laurel.…”

Natural sesquiterpenoids

“…409 The novel lactone 490 has been found in the study of an extract from Laurus nobilis. 370 An enantioselective synthesis of the (1S,5R)-enantiomer of litseaverticillol A and litseaverticillol B has been accomplished. 410 On the other hand, successful biomimetic syntheses of the litseaverticillol family of sesquiterpenes have been achieved, using singlet oxygen chemistry.…”

Isolation and Functional Characterization of Carotenoid Cleavage Dioxygenase-1 from Laurus nobilis L. (Bay Laurel) Fruits

“…Bay leaf (Laurus nobilis) is a characteristic evergreen Mediterranean tree that belongs to the family Lauraceae, and is one of the most widely used culinary spices in the Mediterranean countries, in Europe, and in the U.S. , Fresh or dried bay leaves are used extensively in the food industry, and the essential oil traditionally has been used as herbal medicine and has pharmacological activity that includes antibacterial, antifungal, antidiabetes, and anti-inflammatory effects. − In addition, laurel essential oil was reported to be used by the cosmetic industry in creams, perfumes, and soaps for its antidandruff activity and for the external treatment of psoriasis. , …”