João Pedro Miranda Rocha’s research while affiliated with Federal University of Lavras and other places

Baccharis L. é um gênero de plantas da família Asteraceae, comum no Brasil, especialmente nas regiões Sul, Sudeste e Centro-Oeste. As plantas desse gênero se adaptam a diferentes ambientes e podem variar de arbustos a árvores de pequeno porte. São valorizadas por suas variadas propriedades medicinais. No entanto, apenas cerca de 15% das espécies foram analisadas do ponto de vista fitoquímico. Baccharis também tem um papel econômico significativo, contribuindo para a prevenção da erosão e sendo valorizadas como plantas ornamentais. A pesquisa científica tem revelado um potencial significativo para aplicações farmacêuticas de algumas espécies de Baccharis, aumentando o interesse por este gênero no campo da medicina e da saúde. Este trabalho visou realizar um levantamento de espécies de plantas do gênero Baccharis na região da Serra de Carrancas, em Minas Gerais. Onde foram identificadas 13 espécies distintas pertencentes ao gênero Baccharis, logo após foi feita a validação dos binômios botânicos e seus respectivos autores. Com essas espécies realizamos um levantamento bibliográfico dos registros etnobotânicos e farmacológicos.

Baccharis L. é um gênero de plantas da família Asteraceae, comum no Brasil, especialmente nas regiões Sul, Sudeste e Centro-Oeste. As plantas desse gênero se adaptam a diferentes ambientes e podem variar de arbustos a árvores de pequeno porte. São valorizadas por suas variadas propriedades medicinais. No entanto, apenas cerca de 15% das espécies foram analisadas do ponto de vista fitoquímico. Baccharis também tem um papel econômico significativo, contribuindo para a prevenção da erosão e sendo valorizadas como plantas ornamentais. A pesquisa científica tem revelado um potencial significativo para aplicações farmacêuticas de algumas espécies de Baccharis, aumentando o interesse por este gênero no campo da medicina e da saúde. Este trabalho visou realizar um levantamento de espécies de plantas do gênero Baccharis na região da Serra de Carrancas, em Minas Gerais. Onde foram identificadas 13 espécies distintas pertencentes ao gênero Baccharis, logo após foi feita a validação dos binômios botânicos e seus respectivos autores. Com essas espécies realizamos um levantamento bibliográfico dos registros etnobotânicos e farmacológicos.

Hyptis suaveolens is a medicinal and aromatic species that exhibits insecticidal, fungicidal, bactericidal, and nematicidal activity. Its roots contain podophyllotoxin (PTOX), a lignan used by the pharmaceutical industry. Elicitors can stimulate the in vitro production of PTOX. Thus, the aim of this study was to evaluate the use of biotic and abiotic elicitors in the production of PTOX in root culture. Roots of plantlets grown in vitro were excised, weighed, and inserted into Erlenmeyer flasks containing 50.0 mL of Murashige and Skoog (MS) medium and cultivated with different biotic elicitors: melatonin, serotonin, methyl jasmonate, salicylic acid, and chitosan, and abiotic elicitor: light quality. After 42 d, the fresh and dry weight of the roots and the production of PTOX in the roots and medium were assessed. Cultivation under red LED light increased the accumulation of PTOX in the medium and the dry weight of the roots. However, the concentrations of 50.0 and 100.0 mg L−1 of chitosan provided the best results in terms of total PTOX production. The addition of 30.0 µM melatonin was responsible for the highest PTOX production. Elicitation with 10.0 µM of serotonin promoted a higher production of fresh and dry root biomass and better growth indices. Supplementing MS culture medium with 5.0 and 10.0 mM of methyl jasmonate favored root growth while the use of 5.0 mM benefited PTOX production. The addition of 50.0 mM of salicylic acid provided a higher production of PTOX in the roots. The use of biotic and abiotic elicitors influenced the increase in root biomass and PTOX production through root culture.

Different growth regulators have been applied to several medicinal plant species to help increasing secondary metabolites’ production in them. The aim of the current study is to analyze the effect of growth regulators’ application, at different concentrations, on Melissa officinalis dry weight production, total phenol and soluble protein contents, and essential oil content and chemical composition. The study has followed a completely randomized design, at 3x3+1 factorial arrangement, which comprised three growth regulators [naphthalene acetic acid (NAA), benzylaminopurine (BAP) and gibberellic acid (GA3)] at three different concentrations (25, 50 and 100 mg L-1), as well as the additional treatment (control), with 4 replications. Growth regulators applied at different concentrations have significantly influenced Melissa officinalis growth. GA3 and NAA regulators’ application at 100 mg L-1 has favored the shoot length and total leaf area of the investigated species. BAP application on leaves, at the highest concentration, led to apical dominance loss; however, the lowest concentration of it has favored soluble protein concentrations in the leaves. BAP application at 25 mg L-1 has favored protein concentrations in the leaves. The highest total phenol contents were observed in plants sprayed with increasing GA3 and BAP doses; they did not differ from the control treatment, only. Essential oil compounds varied depending on the adopted growth regulator type and concentration. GA3 application at the lowest dose (25 mg L-1) resulted in citral content increase by 18% and in citronellal compound content gain ranging from 8% to 10%.

Hyptis suaveolens (L.) Poit is known for containing podophyllotoxin (PTOX), a natural lignan used as the lead compound in antitumor agent preparations, in its roots. The use of phloroglucinol (PHL) and indoleamines, such as melatonin (MEL) and serotonin (SER), in plant tissue culture is a promising alternative for eliciting rare and high-value secondary metabolites of medical importance. Aimed to evaluate the impact of different concentrations of PHL, either alone or in combination with MEL or SER, on the growth and accumulation of PTOX in H. suaveolens. Apical segments were vertically inoculated in MS medium containing different concentrations of MEL or SER (0; 0.25; 0.50; 1.00; 5.00 and 10.00 µM) and PHL (0 and 50 mg L⁻¹). After 40 days, growth parameters, chlorophyll content and PTOX content were assessed. Plantlet rooting and root dry weight notably increased with the use of 0.5 µM MEL alongside PHL. Overall, treatments containing PHL showed superior results, except for chlorophyll content. SER supplementation was effective in increasing root growth, root number and leaf area. The combination of 1.0 µM MEL or SER and 50 mg L⁻¹ PHL increased the production of PTOX in the roots of H. suaveolens by 2.0 and 1.6 times, respectively. In conclusion, the application of PHL and indoleamines demonstrated an eliciting effect on both growth and PTOX production in H. suaveolens roots, presenting a promising avenue for further research and application in eliciting targeted secondary metabolites.

Green manure (GM) may reduce the use of chemical fertilizers, been an ecologically appropriate strategy to cultivation of medicinal plants. Crotalaria juncea, is one of the most used because it adapts to different climatic and high nitrogen content. Origanum vulgare. is widely used in cooking, pharmaceutical, cosmetic industries and food products. The objectives of this study were to evaluate the GM on biomass, essential oil (EO), phenolic and antioxidant. The experiment consisted: control; 150, 300, 450, and 600 g (Sh= leaves+steam) more 200 g roots (R); 600 g aerial part; 200 g roots; and soil with 300 g cattle manure per pot. The highest dry weights were observed in the presence of GM and cattle manure (90 days). The control had an EO production 75% lower in relation to the dose of 450 g GM (Sh+R). Principal component analysis showed that GM and cattle manure positively influenced the dry weight, content, yield, and EO constituents, and total flavonoids. The GM contributed to the accumulation of the major EO compounds (trans-sabinene hydrate, thymol, terpinen-4-ol). The GM management may be beneficial for cultivating, because it can increase the production of biomass and the active components, in addition to being an inexpensive resource.

Light is one of the factors that influence the growth, development and synthesis of secondary metabolites of different plant species in vitro. Origanum majorana is an aromatic plant belonging to a group of plants that produce arbutin, a substance of importance in the cosmetic industry. The objective of this study was to verify the effect of light intensity and wavelength on the growth and accumulation of arbutin in vitro in plantlets. Nodal segments were grown in MS culture medium under photon flux densities of 26, 51, 69, 94 and 130 µmol m⁻² s⁻¹. In the light spectrum, nodal segments were grown under different light-emitting diodes LED: red; blue; a combination of blue and red light (30% B:70% R; 50% B:50% R; 70% B:30% R); and white, yellow and green. After 40 days, the growth, photosynthetic pigments and arbutin accumulation were evaluated by HPLC-DAD. The lowest light intensity (26 µmol m⁻² s⁻¹) provided a higher content of photosynthetic pigments, and the intensity of 94 µmol m⁻² s⁻¹ increased dry biomass accumulation. Greater accumulation of arbutin was observed under a higher light intensity of 130 µmol m⁻² s⁻¹. Regarding the quality of light, different wavelengths did not significantly affect the number of shoots or shoot length. The white light spectrum stimulated a greater accumulation of dry biomass. The green light provided a greater accumulation of photosynthetic pigments. The amount of arbutin was influenced by the different light spectra. The red spectrum promoted the highest arbutin content, and the yellow inhibited. Graphical abstract