Oil extraction from green coffee seeds generates residual mass that is discarded by agribusiness and has not been previously studied. Bioactive secondary metabolites in coffee include antioxidant phenolic compounds, such as chlorogenic acids. Coffee seeds also contain caffeine, a pharmaceutically important methylxanthine. Here, we report the chemical profile, antioxidant activity, and cytotoxicity of hydroethanolic extracts of green Coffea arabica L. seed residue. The extracts of the green seeds and the residue have similar chemical profiles, containing the phenolic compounds chlorogenic acid and caffeine. Five monoacyl and three diacyl esters of trans-cinnamic acids and quinic acid were identified by ultra-performance liquid chromatography/electrospray ionization-quadruple time of flight mass spectrometry. The residue extract showed antioxidant potential in DPPH, ABTS, and pyranine assays and low cytotoxicity. Thus, coffee oil residue has great potential for use as a raw material in dietary supplements, cosmetic and pharmaceutical products, or as a source of bioactive compounds.
Rationale
Clerodane‐type diterpenes from Casearia species show important pharmacological activites such as antitumor, antimicrobial and anti‐inflamatory. There are several mass spectrometry (MS)‐based methods for identification of diterpenes; however, there is still a lack of MS procedures capable of providing characteristic fragmentation pathways for a rapid and unambiguous elucidation of casearin‐like compounds.
Methods
Casearin‐like compounds were investigated by electrospray ionization tandem mass spectrometry (ESI‐MS/MS). The fragmentation studies were carried out by tandem mass spectrometry in space (quadrupole time‐of‐flight (QTOF)) using different collision energies and also by tandem mass spectrometry in time (QIT) by selective isolation of product ions.
Results
Casearin‐like compounds presented a predominance of sodium‐ and potassium‐cationized precursor ions. Both QIT and QTOF techniques provided sequential neutral losses of esters related to the R1 to R5 substituents linked to the nucleus of the clerodane diterpenes. The fragmentation pathway is initiated with a cleavage of the ester moieties R2 followed by the elimination of the ester groups R3, both losing neutral carboxylic acids. Using QIT, it was also possible to observe the cleavage of the ester groups R1 or R5 by MS4 experiments.
Conclusions
Through a rational analysis of the fragmentation mechanisms of Casearia diterpenes it was possible to suggest an annotation strategy based on the sequential cleavages of the ester groups related to the R2, R3 and R5 substituents. These results will assist studies of the dereplication and metabolomics involving casearin‐like compounds present in complex extracts of Casearia species.
Casearia sylvestris is an endemic tree of the Latin America that the essential oil (EO) has anti‐inflammatory and gastroprotective actions. This study evaluates the chemical composition of the EO from the volatile fractions of in natura, fresh, and dried C. sylvestris var. sylvestris and var. lingua leaves. For both varieties, the dried leaves presented higher EO yield as compared to fresh leaves. The major EO chemical components were (E)‐caryophyllene, α‐humulene, germacrene D, bicyclogermacrene, spathulenol, caryophyllene oxide, and humulene epoxide II. In both varieties, the content of sesquiterpene hydrocarbons decreased and oxygenated sesquiterpenes increased on going from in natura to fresh and dried leaves, which indicated that leaf drying and hydrodistillation modified the volatile composition. The results also suggested that bicyclogermacrene and (E)‐caryophyllene were oxidized during processing, to generate spathulenol and caryophyllene oxide, respectively. C. sylvestris varieties and in natura, fresh, and dried leaves differed in terms of the chemical composition of volatiles, which could affect the EO biological activities.
Oral preparations of Casearia sylvestris (guacatonga) are used as antacid, analgesic, anti-inflammatory and antiulcerogenic activities. The clerodane diterpenes casearin B (cas B) and caseargrewiin F (casg F) are major active compounds in vitro and in vivo. The oral bioavailability and metabolism of cas B and casg F were not previously investigated. We aimed to assess the stability of cas B and casg F in physiological conditions and their metabolism in human liver microsomes (HLM). The compounds were identified by UHPLC-QTOF-MS/MS and quantified by validated LC-MS methods. The stability of cas B and casg F in physiological conditions was assessed in vitro. Both diterpenes showed a fast degradation (p < 0.05) in simulated gastric fluid. Their metabolism is not mediated by cytochrome P-450 enzymes, but the depletion was inhibited by the esterase inhibitor NaF. Both diterpenes and their dialdehydes showed log P in the range of 3.6 to 4.0, suggesting high permeability. Metabolism kinetic data were fitted to the Michaelis-Menten profile with KM values of 61.4 μM and 66.4 μM and Vmax values of 327 and 648 nmol/min/mg of protein for cas B and casg F, respectively. Metabolism parameters in HLM were extrapolated to predict human hepatic clearance and suggest that casg F and cas B have a high hepatic extraction ratio. In conclusion, our data suggest that casg F and cas B present low oral bioavailability due to extensive gastric degradation and high hepatic extraction.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.