Raulinoreitzia (Koiti and Hattori, 2013)

de Souza, Tiago J. T., S, Bordignon, ergio A. L., Apel, Miriam A. & Henriques, Amelia T., 2021, Volatile constituents of Eupatorieae (Asteraceae). Compositional multivariate analysis of volatile oils from Southern Brazilian species in the subtribe Disynaphiinae, Phytochemistry (112734) 186, pp. 1-23 : 9-14

2.2. Genus Raulinoreitzia

Raulinoreitzia tremula (Hook. & Arn.) R.M.King & H.Rob. and Raulinoreitzia crenulata (Sprengel) R.M.King & H.Rob. (sampled in this study) are, together with R. leptophlebia , the only three species recognized in the genus Raulinoreitzia ( Koiti and Hattori, 2013) . The chemical composition of VOs obtained from both the leaves and inflorescences of R. tremula (syn. Eupatorium tremulum - common name: “chirca”, “vassour˜ao-do-brejo”), a 2–3 m tall, densely branched shrub, native to southern Brazil, Uruguay, and Northeastern Argentina ( King and Robinson, 1987; Matzenbacher, 1979) are quite similar with the predominance of sesquiterpenes (97.2 and 84.0%). Among the hydrocarbon sesquiterpenes (46.0 and 49.7%), compounds bearing a bisabolane nucleus were predominant: β- bisabolene (15.5 and 17.1%), β- sesquiphellandrene (7.9 and 7.1%); alongside the cadinane amorpha-4,7 (11)-diene (11.7 and 10.5%). Among the oxygenated sesquiterpenes, furanocadinanes verboccidentafuran (16.1 and 11.6%) and 3-oxo-verboccidentafuran (3.6 and 14.7%), and alcohols epi-α- bisabolol (9.6 and 10.7%) and amorpha-4-en-7-ol (7.5 and 6.6%) were the most abundant. The presence of sesquiterpene compounds with a bisabolane nucleus is not common in this subtribe, nor are furan compounds. However, other samples of R. tremula collected from different populations in RS have been reported to have qualitatively similar compositions ( de Souza et al., 2017). This species occurs in swampy humid fields and edges of floodable galleries ( Koiti and Hattori, 2013). Together with Hatschbachiella tweediena (Eupatoriinae subtribe), it is important in the reproductive biology of the rusty-collared seedeater Sporophila collaris ( Rosoni, 2017; Rosoni et al., 2019). This species has been implicated in cattle intoxication ( Lucioli et al., 2007) and its extracts exhibit cytotoxicity in vitro against tumor cells ( Monks et al., 2002). A direct link between these activities and a particular chemical compound has not been established to date, but the participation of their characteristic furanocadinenes cannot be ruled out.

The chemical composition of VOs obtained from R. crenulata , a 2 m tall, white-flowered shrub native to Central, Southern, and Northeastern Brazil, Peru, Bolivia, and Northern Argentina ( King and Robinson, 1987; Matzenbacher, 1979) was quite similar to another sample of this species reported by our group and collected from the same area ( Souza et al., 2007), with a slight predominance of hydrocarbon monoterpenes over sesquiterpenes: β- pinene (19.1%) and α- pinene (14.6%) were the main monoterpenes, and β- caryophyllene (7.3%), germacrene D (11.4%), and

Table 2 (continued)

Legend

a Retention Index in a DB5 column b inflorescences

c aerial parts

d leaves

e Aliphatics

f Hydrocarbon Monoterpenes

g Oxygenated Monoterpenes

h Hydrocarbon Sesquiterpenes

i Oxygenated Sesquiterpenes

j

traces.

Table 3 (continued)

bicyclogermacrene (9.7%), the main sesquiterpenes. In the previously reported sample, there were higher amounts of β- myrcene (15.3%) and limonene (22.8%), while the percentage of α- pinene (14.6%) and α- thujene (7.1%) were higher. This is an important species in the reproductive biology of black-bellied seedeaters ( Sporophila melanogaster ) (in the same way as Gyptidinae Barrosoa betoniciiformis ) ( Rovedder, 2011; Rovedder and Fontana, 2012), red-eyed Vireo ( Vireo olivaceus ), and Long-tailed Reed-Finch ( Donacospiza albifrons ) (similarly to Grazielia intermedia ) ( Maurício et al., 2013). The VOs were previously analyzed, yielding 0.54–0.68% (dry and fresh inflorescences, respectively), but the chemical composition was not reported ( Souza, 2015). Another report from Paran´a, Brazil, described limonene (39%) and δ- cadinene (8%) as the major compounds and their activity against the strawberry aphid Aphis forbesi ( Maleski et al., 2019) . Despite sharing the same origin, the chemical composition reported here shows qualitative differences regarding our previous report on this species, reflecting the known variability of volatile chemistry. The composition described for the Parana´samples was even more deviant in their values for limonene, to which the anti-aphid activity of R. crenulata oil was credited ( Maleski et al., 2019).

To the best of our knowledge, the only known reports on the VOs of R. tremula are from RS ( de Souza et al., 2017) and no description has ever been given for the chemical composition of the other species in the genus R. leptophlebia . To date, the volatile chemistry of the genus Raulinoreitzia is very basal for R. crenulata in both Parana´and RS, and extremely atypical for R. tremula in RS. In this way, more samples of R. tremula and R. leptophlebia are needed to better describe this genus.