Antileishmanial activity of essential oil and 6,7-dehydroroyleanone isolated from Tetradenia riparia

Abstract

Tetradenia riparia plant is used as a traditional medicine in Africa for the treatment of inflammatory and infectious diseases as like parasitic. Therapy for leishmaniasis caused by Leishmania (Leishmania) amazonensis specie often fails, and the conventional drugs are toxic, expensive, require a long period of treatment, and adverse effects are common. The alternative therapies using natural products are inexpensive and have few or any adverse reaction. These reasons are sufficient to investigate the new natural therapeutic for leishmaniasis. We evaluated the potential of the essential oil (TrEO) and 6,7-dehydroroyleanone (TrROY) isolated from T. riparia on L. (L.) amazonensis promastigote and amastigote forms, cytotoxicity on human erythrocytes and murine macrophages, nitric production and inducible nitric oxide synthase (iNOS) mRNA expression. TrEO was the most effective to promote the Leishmania promastigote death. After 72 h incubation, the lethal dose of TrEO and TrROY that promoted 50% Leishmania death (LD50) were 0.8 μg/mL and 3 μg/mL, respectively. TrEO and TrROY were not cytotoxic to human erythrocytes, but TrROY was toxic to murine macrophages resulting in a low selectivity index. The transmission electronic microscopy showed that TrEO (0.03 μg/mL) was able to modify the promastigote ultrastructures suggesting autophagy as chromatin condensation, blebbing, membranous profiles and nuclear fragmentation. Infected-macrophages treated with TrEO (0.03 μg/mL) or TrROY (10 μg/mL) had an infection index decreased in 65 and 48%. TrEO did not induce iNOS mRNA expression or nitrite production in macrophages infected with Leishmania. TrROY and mainly TrEO promoted the Leishmania death, and TrROY showed loss toxicity to erythrocytes cells. Other compounds derived from T. riparia and the essential oil could be explored to develop a new alternative treatment for leishmaniasis.

Antileishmanial and immunomodulatory effects of the essential oil from Tetradenia riparia (Hochstetter) Codd

“…without infection or other stimuli) that were treated with TrEO exhibited high production and mRNA expression of IL‐1β, IL‐12, IL‐17, and IFN‐γ. TrEO also downregulated IL‐10 and IL‐6 . In the present study, we observed a similar profile of cytokine modulation, even under pathogenic conditions, suggesting that TrEO is able to modulate cytokines.…”

“…Essential oils, including those of the Lamiaceae family, can stimulate cytokines that mediate the protective cellular immune response against intracellular pathogens, other agents, cancer, and autoimmune disorders . The immunomodulatory and antileishmanial effects that were induced by TrEO may be attributable to its complex mixture of compounds.…”

“…In a previous study, the EO from T. riparia presented excellent analgesic effects when administered orally in mice and inhibited acetic acid‐induced constrictions when administered intra‐abdominally . An extract of T. riparia leaves inhibited the percentage of acetyl cholinesterase, cyclooxygenase 1 (COX‐1) and COX‐2 enzymes, demonstrating an anti‐inflammatory effect . In folk medicine, T. riparia leaves are used for the treatment of respiratory illness (e.g.…”

Photodynamic Therapy With Bengal Rose and Derivatives Against Leishmania amazonensis

“…After incubation at 25°C for 24, 48 and 72 hours, cell viability was measured by the XTT reduction method. 13 The inhibitory concentration of 50% of the parasites (IC 50 ) was calculated by linear regression equation. 13 Peritoneal macrophages BALB/c mice were infected with L. amazonensis promastigotes (6 parasites/ macrophage) as in Honda et al 14 Photosensitizers RBMET (8.…”

“…13 The inhibitory concentration of 50% of the parasites (IC 50 ) was calculated by linear regression equation. 13 Peritoneal macrophages BALB/c mice were infected with L. amazonensis promastigotes (6 parasites/ macrophage) as in Honda et al 14 Photosensitizers RBMET (8. 7 mM) and RBBUT (17.2 mM) were diluted in twofold, the protocol of incubation and illumination was the same as described above.…”