Antitumor activity of arylacetylshikonin analogues

Twenty one phenylacetylshikonin analogues were synthesized from various substituted phenyl acetic acids and their cytotoxicity values against A549, K562 and L1210 cell lines and antitumor action in mice bearing S-180 cells were measured. All of phenylacetylshikonin analogues expressed a potent cytotoxicity (ED₅₀, 0.1–1.80 μg/ml) against L1210 and K562 cells. L 1210 cells were the most sensitive to shikonin analogues among these cells. Except 4-methoxyphenylacetylshikonin (0.098μg/ml) and α-acetoxyphenylacetylshikonin (0.10μg/ml), all other shikonin derivatives showed higher ED₅₀ values than phenylacetylshikonin (0.13μg/ml) in L 1210. In K562 cell, α-substitution of phenylacetylshikonin (0.1 μg/ml), while other substitutions increased it slightly; 4-methoxyphenylacetylshikonin (0.033 μg/ml) showed a exceptionally good cytotoxicity against K562 cell. 4-Halogenation tended to decrease the cytotoxic effect on L1210 cells, while it enhanced the effect on K562; 4-bromophenylacetyl [ED₅₀ (L1210)=1.76 μ/ml, ED₅₀ (K 562)=0.32 μg/ml] and 4-chlorophenylacetyl shikonin [ED₅₀ (L 1210)=1.64 μg/ml, ED₅₀ (K562)=0.32 μg/ml]. In contrast, A549 cells were much less sensitive to these shikonin analogues which showed ED₅₀ values of 1.5–13.5 μg/ml. Most of phenylacetylshikonin derivatives showed good antitumor activity in mice bearing S-180 cells. α-A-cetoxyphenylacetylshikonin and 4-dimethylaminophenylacetylshikonin showed highest T/C value (192–195%), implying that introduction of α-acetyl or of 4-dimethyl amino group gave a positive effect on the antitumor activity. Introduction of 4-dimethylamino group enhanced the antitumor activity as shown for 4-dimethylaminophenylacetylshikonin (T/C, 192%). It might be due to improvement of water solubility by dimethylamino group in the molecule.     

Acetylpanaxydol und Panaxydolchlorhydrin,zwei neue,gegen L1210-Zellen cytotoxische Polyine aus Koreanischem Ginseng

Acetylpanaxydol and Panaxydolchlorohydrin, Two New Poly-ynes from Korean Ginseng with Cytotoxic Activity against L1210 Cells Two new polyines showing good cytotoxic activity against L1210 cells were isolated from Korean ginseng root. These were 3-acetyloxy-9,10-epoxy-heptadec-1-en-4,6-diyne (acetylpanaxydol, ED₅₀= 0.52 μg/nl) and 10-chloro-3,9-dihydroxyherptadec-1-en-4,6-diyne(Panaxydolchlorohydrin, ED₅₀= 0.50 μg/ml).     

Synthesis of benzo[c]phenanthridine derivatives and theirin vitro antitumor activities

Aiming at the development of anticancer agents by modification of phenolic benzo[c]phenanthridine alkaloid, additional hydroxyl group was put on C10 position of fagaridine (1) by a biomimetic synthetic procedure to afford 10-hydroxyfagaridine (12). All of the synthetic intermediates were also screenedin vitro antitumor activities against five different cell lines as well as12. Among them the representative cytotoxic results are shown as follows;p-quinone (11) [ED₅₀ (A549=0.22 μg/ml), (HCT15=0.21 μg/ml), fagaridine (1) (HCT 15=0.41 μg/ml), olefin (6) (HCT 15=0.06 μg/ml), acetal (7) (SKMEL-2=0.07 μg/ml), dihydrofagaridne (10) (A549=0. 38 μg/ml), 10-hydroxyfagaridine (12) (A 549=0.45 μg/ml). From these observation three main remarks can be drawn; (i) the iminium part of benzo[c]phenanthridine is not essential for showing acitvities, (ii) the additional hydroxyl group did not contribute to enhance the cytotoxicity, (iii) the 3-arylisoquinolin-1(2H)-one derivatives were found to display significantin vitro antitumor activity.     

Antitumor activity of pedunculagin,one of the ellagitannin

As a part of trials to develop the antitumor agent from tannins isolated from plants, the antitumor activity of pedunculagin, an ellagitannin, isolated fromAlnus hirsuta var.microphylla-was examinedin vitro andin vivo. In vitro, the cytotoxicity was determined by 0.4% trypan blue dye exclusion method. Pedunculagin showed the dose-dependent cytotoxicity against human chronic myelogenous leukemia (K-562), human promyelocytic leukemia (HL-60), mouse lymphoid neoplasm (P388), mouse lymphocytic leukemia (L1210) and mouse sarcoma 180 (S 180) cell lines. ED₅₀ values (ED₅₀) of each cell line were 5.30, 0.92, 2.78, 9.35 and 1.38 μg/ml respectively. The most sensitive cell line was HL-60.In vivo, pedunculagin was administered to ICR mouse with the doses of 50 and 100 μg/kg intraperitoneally once at 20 days before S180 inoculation. Pedunculagin showed the antitumor activity and its T/C ratio (%) was 120.82% in the group of both concentrations.     

2-(1-Oxyalkyl)-1,4-dioxy-9,10-anthraquinones: Synthesis and evaluation of antitumor activity

Fourty eight derivatives of 2-(1-oxyalkyl)-1,4-dioxy-9,10-anthraquinone were synthesized, and their antitumor activity was evaluated. On the whole, 2-(1-hydroxyalkyl)-1,4-dihydroxy-9,10-anthraquinones (DHAQ=1,4-dihydroxy-9,10-anthraquinone) showed stronger cytotoxic activity againnst L1210 cells than 2-(1-hydroxyalkyl)-1,4-dimethoxy.-9,10-anthraquinones(DMAQ=1,4-dimethoxy-9,10-anthraquinone), implying that free hydroxy groups at C-1 and C-4 of the anthraquinone structure are necessary for the cytotoxic activity. The bioactivity of 2-(1-hydroxyalkyl)-DHAQ derivatives differed according to the size of alkyl group at C-1, while the elongation of alkyl group over 7 carbon atoms failed to enhance, the bioactivity, the derivatives possessing alkyl moiety of 1–6 carbon atoms showed an increase in the cytotoxicity and the antitumor activity in Sarcoma-180; 2-hydroxymethyl-DHAQ (ED₅₀, 15 μg/ml; T/C, 125%), 2-(1-hydroxyethyl)-DHAQ(1.9 μg/ml; 139.2%), 2-(1-hydroxypropyl)-DHAQ (7.2 μg/ml; 135.1%), 2-(1-hydroxybutyl)-DHAQ (10.2 μg/ml; 125.3%), 2-(1-hydroxypentyl)-DHAQ (23.7 μg/ml; 110.1%) and 2-(1-hydroxyhexyl)-DHAQ (58 μg/ml; 108%). Next, 2-(1-Hydroxyalkyl)-DHAQ derivatives were acetylated to produce 2-(1-acetoxyalkyl)-DHAQ analogues. Although the acetylation somewhat enhanced the cytotoxicity, but not the antitumor action. In addition, the presence of phenyl group at C-1' enhanced the cytotoxicity and the T/C value, compared to alkyl groups of same size; 2-(1-hydroxy-1-phenyl)-DHAQ (ED₅₀, 5.6 μg/ml; T/C., 137%).     

Inhibition of IL-1 release from human monocytes and suppression of streptococcal cell wall and adjuvant-induced arthritis in rats by an extract of Tripterygium wilfordii Hook

1. It was investigated whether an extract of Tripterygium wilfordii Hook f (TW) inhibits IL-1 production by monocytes and suppresses the development of IL-1-dependent arthritis induced in rats with streptococcal cell wall and adjuvant.2. TW preferentially inhibited IL-1α and IL-1β production by bacterial lipopolysaccharide (LPS)-stimulated human monocytes with IC₅₀ of approximately 1 μg/ml.3. Oral administration of TW dose-dependently suppressed joint swelling and structural damage in streptococcal cell wall-induced arthritis (ED₅₀ = 20 mg/kg/day) and in adjuvant-induced arthritis (ED₅₀ = 46 mg/kg/day for developing and 8/mg/kg/day for established arthritis).     

A cytotoxic component from Angelicae Koreanae Radix against L1210 and HL-60 cells

A cytotoxic sesquiterpene against L1210 and HL-60 cells was isolated from Angelicae Koreanae Radix (buk-kang-hwal). The component was identified as bisabolangelone by means of chemical and physical methods. The ED₅₀ values of it were 1.20 μg/ml against L1210 cells and 2.30 μg/ml against HL-60 cells. Bisabolangelone was found in buk-kang-hwal but not in kang-hwal.     

A cytotoxic constituent fromSophora flavescens

A cytotoxic constituent was isolated by bioassay-guided procedure from the roots ofSophora flavescens Aiton (Leguminosae). The constituent was identified as sophoraflavanone G (I) by means of chemical methods and in comparsion with spectral data of standard compound. The ED₅₀ values of constituent I were 0.78, 1.57, 2.14 and 8.59 μg/ml against A549, HeLa, K562 and L1210 cell lines respectively. ConstituentI exhibited highly cytotoxic activities against A 549, K562 and HeLa cells, but showed a mild activity (ED₅₀ value, 5 μg/ml) against L1210 cells. Among the tested cell lines, A549 cells were the most sensitive to constituentI.     

Cytotoxic Effects of Tris (2,3-dibromopropyl) phosphate and 2,4-diaminoanisole

Abstract The flame retardant tris(2,3-dibromopropyl)phosphate (Tris-BP) and the hair-dye component 2,4-diaminoanisole (2,4-DAA) were studied for possible cytotoxic effects in rat hepatoma cells grown in culture and in suspensions of isolated rat hepatocytes. Cell growth of Reuber cells was inhibited by 50% at 50 μg/ml Tris-BP and 20 μg/ml 2,4-DAA, respectively. At 200 μg/ml Tris-BP protein synthesis in Reuber cells was reduced by 40%, whereas 50% inhibition of protein synthesis in isolated hepatocytes was seen at 100 μg/ml. IC50 of 2,4-DAA with respect to protein synthesis was found at 400 μg/ml in Reuber cells and at 3600 μg/ml in MH₁C₁ cells, whereas in the isolated hepatocytes IC50 was 650 μg/ml. DNA synthesis was inhibited by 50% at 225 μg/ml Tris-BP in Reuber cells. At 500 μg/ml 2,4-DAA DNA synthesis in Reuber and MH₁C₁ cells was inhibited by more than 80%.     

Cytotoxic Activities of Salvia. of the Labiatae Family

ABSTRACT

Eight crude extracts of five Salvia. species were evaluated for cytotoxic activities against brine shrimps and four human cancer cell lines [human colon adenocarcinoma (HCA), HepG2, MCF-7, and human pancreatic carcinoma (HPC) along with a normal mouse cell line (areolar cells)] as a control. In the brine shrimp lethality test, all samples, except S. fruticosa. L. (Sifnos collection) and S. verbenaca. L. (Zante collection), were found to be highly active with ED₅₀ values less than 300?μg/ml. In the case of human cancer cell lines, S. fruticosa., collected from Kalymnos and Crete, were active against HCA cells with LC₅₀?=?60.4 and 40.1?μg/ml respectively. Interestingly, only one sample, S. fruticosa. collected from Kalymnos, was active against HepG2 cells with LC₅₀?=?68.1?μg/ml. In the case of MCF-7 cells, S. fruticosa. collected from three different locations (Kalymnos, Rhodos, and Crete) showed similar activity with LC₅₀?=?43.1, 41.1, and 42.3?µg/ml, respectively. All S. fruticosa. samples were found to be cytotoxic toward a normal mouse cell line when tested at 0.1?mg/ml. All the other samples had LC₅₀ values greater than 75?µg/ml,and were considered to be inactive.     

Anti-inflammatory and diuretic effects of the diterpene ent-dihydrotucumanoic acid

Gymnosperma glutinosum (Spreng) Less (Asteraceae) is a shrub used in traditional medicine for the treatment of inflammatory and renal diseases. The ent-dihydrotucumanoic acid (DTA) is a diterpene obtained from G. glutinosum. This study evaluated the antioxidant, genotoxic, and diuretic properties of DTA, as well as its in vitro and in vivo anti-inflammatory actions. The antioxidant actions of DTA were assessed with the 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), ferric reducing antioxidant power (FRAP), and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) assays, the genotoxic action was assessed with the comet assay, and the diuretic effects of DTA were assessed using metabolic cages. The anti-inflammatory actions were evaluated using primary murine peritoneal macrophages stimulated with LPS and the λ-carrageenan-induced hind paw edema test. DTA lacked antioxidant (IC₅₀ > 25,000 μg/mL) activity in the ABTS, FRAP, and DPPH assays. DTA at 500–1,000 μg/mL showed moderate genotoxicity. In LPS-stimulated macrophages, DTA showed IC₅₀ values of 74.85 μg/mL (TNF-α) and 58.12 μg/mL (NO), whereas the maximum inhibition of IL-6 (24%) and IL-1β (36%) was recorded at 200 μg/mL. DTA induced in vivo anti-inflammatory effects with ED₅₀ = 124.3 mg/kg. The in vitro anti-inflammatory activity of DTA seems to be associated with the decrease in the release of TNF-α and NO. DTA promoted the excretion of urine (ED₅₀ = 86.9 mg/kg), Na⁺ (ED₅₀ = 66.7 mg/kg), and K⁺ (ED₅₀ = 8.6 mg/kg). The coadministration of DTA with L-NAME decreased the urinary excretion shown by DTA alone. Therefore, the diuretic activity is probably associated with the participation of nitric oxide synthase. In conclusion, DTA exerted anti-inflammatory and diuretic effects, but lacked antioxidant effects.     

1H‐1,2,3‐Triazole tethered isatin‐moxifloxacin: Design,synthesis and in vitro anti‐mycobacterial evaluation

A series of novel 1H‐1,2,3‐triazole tethered isatin–moxifloxacin (MXF) hybrids 5a ‐ l with greater lipophilicity compared with the parent MXF were designed, synthesized and screened for their in vitro antimycobacterial activities against Mycobacterium tuberculosis (MTB) H₃₇Rv and multidrug‐resistant MTB (MDR–MTB) as well as their cytotoxicity on the VERO cell line. All the synthesized hybrids (MIC: 0.025‐0.78 μg/ml) showed considerable activities against MTB H₃₇Rv and MDR–MTB, and the most active conjugate 5c (MIC: 0.025 and 0.06 μg/ml) was 2 to >2048 times more potent in vitro than the three references MXF (MIC: 0.10 and 0.12 μg/ml), rifampicin (MIC: 0.39 and 32 μg/ml) and isoniazid (MIC: 0.05 and >128 μg/ml) against the two tested strains. All hybrids (CC₅₀: 4‐64 μg/ml) were much more cytotoxic than the parent MXF (CC50: 128 μg/ml), but the most active hybrid 5c (CC₅₀: 32 μg/ml) also displayed acceptable cytotoxicity, warranting further investigation.     

The cytotoxic activity of amorphous silica nanoparticles is mainly influenced by surface area and not by aggregation

The aggregation state of NP has been a significant source of difficulty for assessing their toxic activity and great efforts have been done to reduce aggregation of and/or to disperse NP in experimental systems. The exact impact of aggregation on toxicity has, however, not been adequately assessed.Here we compared in vitro the cytotoxic activity of stable monodisperse and aggregated silicon-based nanoparticles (SNP) without introducing a dispersing agent that may affect NP properties.SNP aggregates (180 nm) were produced by controlled electrostatic aggregation through addition of KCl to a Ludox SM sol (25 nm) followed by stabilization and extensive dialysis. The size of the preparations was characterized by TEM and DLS; specific surface area and porosity were derived from N₂ sorption measurements. Macrophage (J774) and fibroblast (3T3) cell lines were exposed to monodisperse or aggregate-enriched suspensions of SNP in DMEM in absence of serum. The cytotoxic activity of the different preparations was assessed by the WST1 assay after 24 h of exposure. Parameters that determined the cytotoxic activity were traced by comparing the doses of the different preparations that induced half a maximal reduction in WST1 activity (ED₅₀) in both cell lines.We found that ED₅₀ (6-9 μg/ml and 15-22 μg/ml, in J774 and 3T3, respectively) were hardly affected upon aggregation, which was consistent with the fact that the specific surface area of the SNP, a significant determinant of their cytotoxic activity, was unaffected upon aggregation (283-331 m²/g). Thus studying small aggregated NP could be as relevant as studying disperse primary NP, when aggregates keep the characteristics of NP, i.e. a high specific surface area and a nanosize dimension. This conclusion does, however, not necessarily hold true for other toxicity endpoints for which the determinants may be different and possibly modified by the aggregation process.     

Synthesis andin vitro cytotoxicity of cinnamaldehydes to human solid tumor cells

Cinnamaldehydes and related compounds were synthesized from various cinnamic acids based on the 2′-hydroxycinnamaldehyde isolated from the bark ofCinnamomum cassia Blume. The cytotoxicity to human solid tumor cells such as A549, SK-OV-3, SK-MEL-2, XF498 and HCT15 were measured. Cinnamic acid, cinnamates and cinnamyl alcohols did not show any cytotoxicity against the human tumor cells. Cinnamaldehydes and realted compounds were resistant to A549 cell line up to 15 μg/ml. In contrast, HCT15 and SK-MEL-2 cells were much sensitive to these cinnamaldehyde analogues which showed ED₅₀ values 0.63-8.1 μg/ml. Cytotoxicity of the saturated aldehydes was much weak compared to their unsaturated aldehydes. From these studies, it was found that the key functional group of the cinnamaldehyde-related compounds in the antitumor activity is the propenal group.     

In vitro activities of LB20304, a new fluoroquinolone

Thein vitro activity of LB20304 was evaluated against clinical isolates and compared with those of Q-35, ciprofloxacin, sparfloxacin, lomefloxacin and ofloxacin. LB20304 demonstrated 16- to 64-fold more potent activity than ciprofloxacin against gram-positive bacteria. LB20304 inhibited 90% of the isolates of methicillin-susceptibleStaphylococcus aureus (MSSA) at a concentration of 0.016 μg/ml (MIC₉₀). MIC₉₀ values of LB20304 against methicillin-resistantStaphylococcus aureus (MRSA), methicillin-susceptibleStaphylococcus epidermidis (MSSE), methicillin-resistantS. epidermidis (MRSE) andStreptococcus pneumoniae were 2 μg/ml, 0.016 μg/ml, 0.5 μg/ml and 0.031 μg/ml, respectively. LB20304 was also very active against gram-negative bacteria. AgainstEscherichia coli, Klebsiella pneumoniae, Serratia marcescens, Pseudomonas aeruginosa andAcinetobacter calcoaceticus, MIC₉₀S of LB20304 were 0.031 μg/ml, 0.25 μg/ml, 2 μg/ml, 8 μg/ml and 0.5 μg/ml, respectively. Its activity was comparable to that of ciprofloxacin but much better than those of Q-35, sparfloxacin, ofloxacin and lomefloxacin. LB20304 also exhibited the most potent activity among quinolones tested against laboratory standard strains, ofloxacin-resistant strains, β-lactamase-producing strains and anaerobic strains. The inhibitory effect (IC₅₀) of LB20304 on DNA gyrase fromMicrococcus luteus, determined by the supercoiling assay, was 8-fold more potent than that of ciprofloxacin. LB20304 did not induce topoisomerase-associated DNA cleavage even at a concentration of 10 mg/ml, although ciprofloxacin induced DNA cleavage at a concentration of 1 mg/ml.     

Dopamine enhancement of dextrorphan-induced skin antinociception in response to needle pinpricks in rats

BackgroundDextrorphan with long-acting local anesthetic effects did not cause system toxicity as fast as bupivacaine, while catecholamines (i.e., epinephrine) with the vasoconstrictive characteristics enhanced the effects of local anesthetic drugs. The objective of the experiment was to examine the synergistic effect of local dopamine (a catecholamine) injection on cutaneous antinociception of dextrorphan.MethodsThe panniculus reflex in response to skin stimulation with a needle was used as the primary endpoint when dextrorphan (1.50, 2.61, 5.46, 10.20 and 20.40 μmol) alone, dopamine (16.20, 32.40, 51.60, 60.00 and 81.60 μmol) alone, or dopamine + dextrorphan (a ratio of ED₅₀ vs. ED₅₀) was injected subcutaneously on the rat's back. We used an isobolographic modelling approach to determine whether a synergistic effect would be observed.ResultsWe showed that dextrorphan, dopamine, or the mixture of dopamine and dextrorphan produced dose-related skin antinociception. The potency (ED₅₀, 50% effective dose) for cutaneous antinociception was dextrorphan [6.02 (5.93–6.14) μmol] greater than dopamine [48.91 (48.80–49.06) μmol] (p < 0.01). The duration of nociceptive inhibition induced by dopamine was longer than that induced by dextrorphan (p < 0.01) based on their equipotent doses (ED₂₅, ED₅₀, and ED₇₅). Enhancement and prolongation of skin antinociception occurred after co-administration of dopamine with dextrorphan.ConclusionsWhen compared to dopamine, dextrorphan was more potent and had a shorter duration of skin nociceptive block. Dopamine produced a synergistic effect on dextrorphan-mediated antinociception, and prolonged dextrorphan′s antinociceptive duration.     

Evidence for partial agonist properties of daltroban (BM 13,505) at TP receptors in the anæsthetized open-chest rat

We sought to determine whether the intrinsic pulmonary hypertensive activity of the purported thromboxane A₂/prostanoid (TP) receptor antagonist, daltroban, was mediated by TP receptors, using the high efficacy TP receptor agonist, U-46619, and the silent TP receptor antagonist, SQ 29,548. In pentobarbitone-anæsthetized, open-chest rats (n = 4–10 per group), non-cumulative injections of U-46619, dose-dependently increased mean pulmonary arterial pressure (MPAP) with an ED₅₀ (geometric mean with 95% confidence limits in parentheses) of 1.4 (1.1– 2.3) μg/kg i.v.. Daltroban increased MPAP in a bell-shaped manner, with an apparent ED₅₀ [29 (21–35)μg/kg i.v.] being 21 fold less potent than that of U-46619. The maximal pulmonary hypertensive responses evoked by daltroban represented about half those induced by U-46619 (25.4 ± 1.0 vs. 12.7 ± 2 mmHg; P < 0.05 between groups). The TP receptor antagonist SQ 29,548 fully antagonized increases in MPAP evoked by equihypertensive doses of U-46619 (1.25 μg/kg) or daltroban (80 μg/kg). Further experiments were carried out to determine whether daltroban antagonized the pulmonary hypertensive responses evoked by the high efficacy agonist, U-46619, or by itself as receptor theory would predict for a partial agonist. Daltroban (10–2500 μg/kg) antagonized, although not fully, U-46619 (20 μg/kg)-evoked pulmonary hypertensive responses, since prominent intrinsic pulmonary hypertensive effects of daltroban were observed in the same range of doses. Furthermore, in contrast to U-46619 (1.25 μg/kg), daltroban (80 μg/kg) failed to evoke a second pulmonary hypertensive response following a previous injection, as would be expected for a partial agonist. Collectively, the results strongly suggest that daltroban behaves as a partial agonist at TP receptors in the pulmonary vascular bed of the rat in vivo.     

Opposing effects of apomorphine on pain in rats. Evaluation of the dose-response curve

The effect of apomorphine on a supraspinally mediated response to pain was studied after subcutaneous administration of 10 different doses (25 μg/kg up to 10 mg/kg). Depending on the dose given, apomorphine was found to induce opposing effects on pain, so that low doses, 25–100 μ/kg, dose-dependently increased the sensitivity to pain. This effect then gradually declined in potency with increasing doses and high doses induced antinociception. The data therefore suggest that the net effect recorded involves the sum of responses from at least two functional systems. Using the Hill equation and the digital computer program NONLIN, we have dissociated the observed effect into two components, each having its particular dose-response characteristics: low doses having an ED₅₀ value of 36 μg/kg produced hyperreactivity to pain, and high doses having an ED₅₀ of 465 μg/kg (in the absence of hyperalgesia) induced antinociception.     

Anti-Trichomonas vaginalis properties of the oil of Amomum tsao-ko and its major component,geraniol

Context: Trichomonosis, caused by the flagellate protozoan Trichomonas vaginalis, is the most common non-viral sexually transmitted disease (STD) and 5-nitroimidazole drugs are used for the treatment. However, a growing number of T. vaginalis isolates are resistant to these drugs, which make it becomes an urgent issue.

Objective: The current study was designed to evaluate the anti-T. vaginalis activity of the essential oil from A. tsao-ko used in traditional Chinese medicine and as a spice and its main component, geraniol.

Materials and methods: The anti-T. vaginalis activities of A. tsao-ko essential oil and geraniol were evaluated by the minimum lethal concentration (MLC) and 50% inhibitory concentration (IC₅₀) in vitro. The morphological changes of T. vaginalis were observed by transmission electron microscopy (TEM). Additionally, sub-MLC concentration treatment with sub-MLC A. tsao-ko essential oil and geraniol was also performed.

Results: This study shows that MLC/IC₅₀ of A. tsao-ko essential oil was 44.97?µg/ml/22.49?µg/ml for T. vaginalis isolate Tv1, and 89.93?µg/ml/44.97?µg/ml for T. vaginalis isolate Tv2. Those of geraniol were 342.96?µg/ml/171.48?µg/ml, respectively. After A. tsao-ko essential oil or geraniol treatment, obvious similar morphological changes of T. vaginalis were observed by TEM: the nuclear membrane was damaged, nuclei were dissolved, and the chromatin was accumulated; in the cytoplasm, numerous vacuoles appeared, rough endoplasmic reticulum dilated, the number of ribosomes were reduced, organelles disintegrated, the cell membrane was partially damaged, with cytoplasmic leakage, and cell disintegration was observed. The action time did not increase the effect of A. tsao-ko essential oil or geraniol against T. vaginalis, as no significant difference was observed after sub-MLC concentration treatment for 1, 3, and 5?h with A. tsao-ko essential oil and geraniol.

Discussion and conclusion: The study describes the first report on the activity and morphological changes of A. tsao-ko essential oil and geraniol against T. vaginalis. The results obtained herein presented new opportunities for antitrichomonal drugs.