Cytotoxicity of Cymbopogon citratus (DC) Stapf fractions, essential oil, citral, and geraniol in human leukocytes and erythrocytes

Synergistic Larvicidal and Pupicidal Toxicity and the Morphological Impact of the Dengue Vector (Aedes aegypti) Induced by Geranial and trans-Cinnamaldehyde

Monoterpenes are effective and eco-friendly alternatives to conventional chemical larvicides. We tested single and binary mixtures of monoterpenes-geranial and trans-cinnamaldehyde-for their larvicidal and pupicidal activities against Aedes aegypti L. and for non-target toxicity on guppies (Poecilia reticulata Peters), using 1% (w/w) temephos as a reference. Geranial and trans-cinnamaldehyde at 250 ppm showed stronger larvicidal and pupicidal activities with a 100% mortality rate and an LT50 ranging from 0.3 to 0.6 h. All combinations were strongly synergistic against larvae and pupae compared to single formulations, with an increased mortality value (IMV) of 6% to 93%. The combination of geranial + trans-cinnamaldehyde (1:1) at 200 ppm showed the highest impact, with an IMV of 93%. The strongest larvicidal and pupicidal activities, a 100% mortality rate, and an LT50 of 0.2 h were achieved by geranial + trans-cinnamaldehyde (1:1) 500 ppm. They were thirty times more effective than a 1% temephos solution (LT50 ranging from 6.7 to 96 h) and caused obviously shriveled cuticles and a swollen respiratory system. All single and binary mixtures were not toxic to the guppies. Thus, the combination of geranial + trans-cinnamaldehyde has great potential as a safe insecticide for controlling mosquito larvae and pupae.

Synergistic Antibacterial Screening of Cymbopogon citratus and Azadirachta indica: Phytochemical Profiling and Antioxidant and Hemolytic Activities

Current studies were performed to investigate the phytochemistry, synergistic antibacterial, antioxidant, and hemolytic activities of ethanolic and aqueous extracts of Azadirachta indica (EA and WA) and Cymbopogon citratus (EC and WC) leaves. Fourier transform infrared data verified the existence of alcoholic, carboxylic, aldehydic, phenyl, and bromo moieties in plant leaves. The ethanolic extracts (EA and EC) were significantly richer in phenolics and flavonoids as compared to the aqueous extracts (WA and WC). The ethanolic extract of C. citratus (EC) contained higher concentrations of caffeic acid (1.432 mg/g), synapic acid (6.743 mg/g), and benzoic acid (7.431 mg/g) as compared to all other extracts, whereas chlorogenic acid (0.311 mg/g) was present only in the aqueous extract of A. indica (WA). Food preservative properties of C. citratus can be due to the presence of benzoic acid (7.431 mg/g). -Gas chromatography-mass spectrometry analysis demonstrated the presence of 36 and 23 compounds in A. indica and C. citratus leaves, respectively. Inductively coupled plasma analysis was used to determine the concentration of 26 metals (Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Sb, Se, Si, Sn, Sr, V, Zn, Zr, Ti); the metal concentrations were higher in aqueous extracts as compared to the ethanolic extracts. The extracts were generally richer in calcium (3000-7858 ppm), potassium (13662-53,750 ppm), and sodium (3181-8445 ppm) and hence can be used in food supplements as a source of these metals. Antioxidant potential (DDPH method) of C. citratus ethanolic extract was the highest (74.50 ± 0.66%), whereas it was the lowest (32.22 ± 0.28%) for the aqueous extract of A. indica. Synergistic inhibition of bacteria (Staphylococcus aureus and Escherichia coli) was observed when the aqueous extracts of both the plants were mixed together in certain ratios (v/v). The highest antibacterial potential was exhibited by the pure extract of C. citratus, which was even higher than that of the standard drug (ciprofloxacin). The plant extracts and their mixtures were more active against S. aureus as compared to E. coli. No toxic hemolytic effects were observed for the investigated extracts indicating their safe medicinal uses for human beings.

Antileishmanial Screening, Cytotoxicity, and Chemical Composition of Essential Oils: A Special Focus on Piper callosum Essential Oil

Leishmania amazonensis is the etiological agent of tegumentary leishmaniasis, a disease characterized by the emergence of cutaneous and mucocutaneous ulcerated lesions that can evolve into severe destruction of skin tissue. Treatment of the disease is often accompanied by high toxicity and variable efficacy. Essential oils stand out for having diverse pharmacological properties. Here, we screened a panel of fourteen essential oils for their anti-L. amazonensis activity, cytotoxicity, and chemical profile. Lippia sidoides (LSEO) and Piper callosum (PCEO) oils displayed the best anti-promastigote and anti-amastigote activities with IC₅₀ of 31 and 21 μg/ml, respectively. PCEO was the safest oil with a desirable selectivity index >10. In addition, PCEO showed no cytotoxicity against the VERO line and erythrocytes. PCEO-treated amastigotes displayed mitochondrial membrane depolarization and high levels of intracellular ROS. Safrole (54.72 %) was the main component of PCEO. The results described here highlight the use of essential oils to combat tegumentary leishmaniasis.