Seasonal Variation on the Contents of Coumarin and Kaurane‐Type Diterpenes in Mikania laevigata and M. glomerata Leaves under Different Shade Levels

Abstract

Coumarin (1) and kaurane-type diterpenes are considered the bioactive constituents of Mikania glomerata and M. laevigata, used in Brazil to treat respiratory affective disorders. The seasonal variation of 1, ortho-coumaric acid (2), benzoylgrandifloric acid (3), cinnamoylgrandifloric acid (4), and kaurenoic acid (5) in leaves of both species, cultivated in full sunlight and under shade levels of 40 and 80%, was quantified by HPLC. Compound 2 was detected solely in M. laevigata in concentrations below the limit of quantification. Coumarin was not found in M. glomerata, whereas its concentration reached 0.94±0.24% (w/w) in M. laevigata farmed in summer under 80% shading. Both Mikania species produced higher amounts of kaurane diterpenes when cultivated in plenty of sunlight. Hence, maximum contents of 1 are reached in M. laevigata cultivated under high shading, but with reduced concentrations of 3-5. Conversely, M. glomerata should be cultivated under full sunlight and harvested in winter for highest concentrations of kaurane-type diterpenes.

Plant toxin levels in nectar vary spatially across native and introduced populations

“…High irradiance and temperature regimes have been known to induce diterpene production in some plant species, as a plastic response to stress conditions (Munne‐Bosch, Schwarz & Alegre ; Bertolucci et al . ). It is thus conceivable that increased levels of GTX I in nectar arise from a similar physiological stress–response in plants, most probably originating in leaves, given the main foliar‐plastid origin of terpenoid biosynthesis (McGarvey & Croteau ).…”

Effect of Accessions and Environment Conditions on Coumarin, O-Coumaric and Kaurenoic Acids Levels of Mikania laevigata

“…Seasonal variation in the bioactive compounds of M. laevigata and Mikania glomerata Spreng. leaves [5] showed the highest coumarin in M. laevigata cultivated in the summer and under 80 % shading, while kaurane-type diterpenes were higher in the winter, but favored by full sunlight. However, no reference was found about different chemotypes of M. laevigata or about the influence of geographic sites.…”

“…The chemical composition of the genus comprises derivatives of cinnamic acid and kaurene-type diterpenes [3]. The major bioactive compounds in the leaves of M. laevigata have been identified as derivatives of cinnamic acids [4,5] like coumarin and o-coumaric acid, along with kaurene-type diterpenes [5] (i.e., kaurenoic acid, benzoylgrandifloric acid, and cinnamoylgrandifloric acid). Coumarin is the chemical marker described [6] and its presence in the leaves of M. laevigata produces the characteristic aromatic smell resembling vanilla [7].…”

“…Another bioactive compound, kaurenoic acid, has been reported for its vasorelaxant and relaxing smooth muscle [14,15], anticonvulsant [16], analgesic [17], and antimicrobial [18,19] properties. Kaurenoic acid is biosynthesized from geranylgeranyldiphosphate (GGDP), a common C 20 precursor for diterpenoids, and this bioactive compound may also be subsequently converted to other metabolites [5] or to bioactive gibberellins (GAs) in flowering plants [20]. In Brazil, the species M. laevigata is widely used due to antiallergic, antispasmodic, anti-inflammatory, antiulcer, antimicrobial, bronchodilator and relaxing smooth muscle properties [1,14,16,17,[21][22][23].…”

“…The Brazilian Pharmacopoeia [24] recommends the use of M. laevigata leaves due to their balsamic effects to alleviate coughing and as an expectorant. The influence of genetic [25] and environmental [5,26] variations on the secondary Abstract ! Coumarin, o-coumaric, and kaurenoic acid are bioactive compounds usually found in the leaves of Mikania laevigata.…”