Antimutagenic effect of broccoli flower head by the ames salmonella reverse mutation assay

A study was performed to investigate the antimutagenic effect of broccoli flower head by the Ames Salmonella reverse mutation assay. Broccoli flower head being the most highly edible part in the plant was analysed for its antimutagenic effect. Without isolating the phytomolecules, the crude ethanol extract of broccoli flower head was tested for suppressing the mutagenic effect induced by certain chemical mutagens. Three strains - TA 98, TA102 and TA 1535 were used in the study. The tester strains were challenged with their respective mutagens. These were challenged with the ethanol extract of broccoli flower head at concentrations of 23 and 46 mg/plate. The plates were incubated for 72 h and the revertant colonies were counted. The crude extract did not prove to be promutagenic. The ethanol extract of the broccoli flower head at 46 mg/plate suppressed the mutagenic effect induced by the corresponding positive mutagens on all the three tester strains used in this study. The crude extract of broccoli flower head alone was not cytotoxic even at the maximum concentration tested (46 mg/plate). In conclusion, the ethanol extract of broccoli at 46 mg/plate suggests their diverse antimutagenic potential against the mutagenic chemicals employed in this study.     

Mutagenic and antimutagenic activities of aqueous and methanol extracts of Euphorbia hirta

Euphorbia hirta (E. hirta) is a weed commonly found in tropical countries and has been used traditionally for asthma, bronchitis and conjunctivitis. However, one of the constituents in this plant, quercetin, was previously reported to be mutagenic. This work aimed to determine the level of quercetin in the aqueous and methanol plant extracts and to investigate the mutagenic effects of quercetin and the extracts in the Ames test utilising the mutant Salmonella typhimurium TA98 and TA100 strains. The antimutagenic activity of Euphorbia hirta aqueous and methanol extracts was also studied in Salmonella typhimurium TA98. HPLC analyses showed that quercetin and rutin, a glycosidic form of quercetin, were present in the acid-hydrolysed methanol extract and non-hydrolysed methanol extract respectively. The quercetin concentration was negligible in both non-hydrolysed and acid-hydrolysed aqueous extracts. The total phenolic contents in Euphorbia hirta were determined to be 268 and 93 mg gallic acid equivalent (GAE) per gram of aqueous and methanol extracts, respectively. Quercetin (25 μg/mL) was found to be strongly mutagenic in Salmonella typhimurium TA98 in the absence and presence of S-9 metabolic activation. However, both the aqueous and methanol extracts did not demonstrate any mutagenic properties when tested with Salmonella typhimurium TA98 and TA100 strains at concentrations up to 100 μg/mL in the absence and presence of S-9 metabolic activation. In the absence of S-9 metabolic activation, both the extracts were unable to inhibit the mutagenicity of the known mutagen, 2-nitrofluorene, in Salmonella typhimurium TA98. On the other hand, the aqueous extracts at 100 μg/mL and methanol extracts at 10 and 100 μg/mL exhibited strong antimutagenic activity against the mutagenicity of 2-aminoanthracene, a known mutagen, in the presence of S-9 metabolic activating enzymes. The results indicated that these extracts could modulate the xenobiotic metabolising enzymes in the liver at the higher concentrations.     

The antimutagenic effect of mistletoe lectin (Viscum album L. var. coloratum agglutinin)

A galactose- and N-acetyl-D-galactosamine-specific lectin (Viscum album L. var. coloratum agglutinin, VCA), which is known for its anticancer activity, was isolated from mistletoe. In this study, we investigated the antimutagenic potentials of VCA by using the pre-incubation method of the Ames test (Salmonella typhimurium TA98 and TA100) in the presence or absence of S9 mixture. Viscum album L. var. coloratum agglutinin was assessed for its antimutagenic properties against the mutagens 2-aminoanthracene (2AA) and furylfuramide (AF-2) for strain TA98, and sodium azide (NaN(3) ) and 2-aminoanthracene (2AA) for strain TA100. The concentrations used for this test compound were 100, 200 and 400 μg per plate. Viscum album L. var. coloratum agglutinin showed moderate, but not negligible, protective effects regarding the antimutagenic properties against the direct-acting mutagens NaN(3) and AF-2. Furthermore, VCA was more effective in preventing the mutagenicity of the indirect-acting mutagen 2-AA (in the presence of S9) when tested with both TA98 and TA100. In conclusion, this report has shown broad ranging antimutagenic effects of VCA to numerous mutagens in TA98 and TA100 Salmonella typhimurium strains. Although the data presented here cannot be applied in vivo, they can support other antimutagenic and anticarcinogenic findings for VCA.     

Antioxidative and antimutagenic activities of healthy herbal drinks from Chinese medicinal herbs

Twenty-nine Chinese medicinal herbs and three healthy herbal drinks made of those herbs in a food processing pilot plant were tested for their antioxidative, free radical scavenging, mutagenic and antimutagenic activities. Water extracts of herbs (with few exceptions) and herbal drinks showed free radical scavenging activity. All water extracts of herbs and herbal drinks showed no mutagenicity toward Salmonella typhimurium tester strains TA98 and TA100 used in the Ames mutagenic tests. In the antimutagenic tests, the mutagenic activity of 4-nitroquinoline N-oxide (NQNO) toward S. typhimurium TA98 was markedly inhibited by water extracts of herbs and herbal drinks. Based on the results, it is suggested that the herbal drinks manufactured in pilot-plant scale are safe and can be served as health-promoting drinks for the public.     

Evaluation of mutagenic and antimutagenic activities of neem (Azadirachta indica) seed oil in the in vitro Ames Salmonella/microsome assay and in vivo mouse bone marrow micronucleus test

Aim of the study

The possible mutagenic and antimutagenic activity of neem oil (NO) and its DMSO extract (NDE) were, examined in the Ames Salmonella/microsome mutagenicity test and the mouse bone marrow micronucleus assay.

Materials and methods

Eight different strains of Salmonella typhimurium were, used to study the genotoxicity of neem oil both in the presence and absence of Aroclor-1254 induced rat liver homogenate (S9). Two-dose treatment protocol was, employed to study the cytogenetic activity in micronucleus assay. Similarly, the antimutagenic activity of neem oil and NDE was studied against mitomycin (MMC) and 7,12-dimethylbenz[a]anthracene (DMBA) in the above two test systems.

Results

Neem oil was non-mutagenic in all the eight tester strains of Salmonella typhimurium both in the presence and absence of S9 mix. In the present study, there was no significant increase in the frequency of micronucleated polychromatic erythrocytes (MNPCEs) in neem oil treated groups over the negative control (DMSO) group of animals, indicating the non-clastogenic activity of neem oil in the micronucleus test. Neem oil showed good antimutagenic activity against DMBA induced mutagenicity compared to its DMSO extract. However, neem oil showed comparatively less antimutagenicity against MMC in the Ames assay. In vivo anticlastogenic assays shows that neem oil exhibited better activity against DMBA induced clastogenicity.

Conclusion

These results indicate non-mutagenic activity of neem oil and significant antimutagenic activity of neem oil suggesting its pharmacological importance for the prevention of cancer.     

Absence of mutagenic effects of a particular Symphytum officinale L. liquid extract in the bacterial reverse mutation assay

Comfrey (Symphytum officinale L.) root is traditionally used for the topical treatment of contusions, strains and sprains. Besides allantoin and rosmarinic acid, which are discussed as pharmacologically active principles, the drug contains pyrrolizidine alkaloids (PAs) known for their hepatotoxic, carcinogenic and mutagenic properties. The topical herbal medicinal products Kytta‐Salbe^® f and Kytta‐Plasma^® f contain a PA‐free liquid extract from comfrey root as active substance. The aim of this study was to demonstrate the absence of genotoxic effects of this special extract in the bacterial reverse mutation assay (Ames test). Briefly, comfrey root liquid extract was investigated for its ability to induce gene mutations in Salmonella typhimurium strains TA 98, TA 100, TA 102, TA 1535 and TA 1537 with and without metabolic activation using the mammalian microsomal fraction S9 mix. Reference mutagens were used to check the validity of the experiments. Comfrey root fluid extract showed no biologically relevant increases in revertant colony numbers of any of the five tester strains, neither in the presence nor in the absence of metabolic activation. In conclusion, the comfrey root fluid extract contained in Kytta‐Salbe^® f and Kytta‐Plasma^® f was not mutagenic in the bacterial reverse mutation assay. Copyright © 2009 John Wiley & Sons, Ltd.     

蜂胶遗传毒性研究

目的探讨蜂胶的遗传毒性,为其应用提供安全性毒理学评价依据。方法用鼠伤寒沙门细菌营养缺陷型突变株TA97(a)、TA98、TA100和TA102,采用平板掺入法进行Ames试验,将实验分为加和不加代谢激活系统S9 2组平行试验。受试物蜂胶设5个剂量组(0.005、0.025、0.250、1.000、5.000 mg/皿)。应用小鼠骨髓嗜多染红细胞微核试验,检测小鼠骨髓嗜多染红细胞微核率;利用小鼠精子畸形试验,观察不同浓度的蜂胶致小鼠精子畸形的数目。结果在Ames试验中,蜂胶各剂量组引起的回变菌落数未超过对照组自发回变菌落数的1倍以上;小鼠骨髓嗜多染红细胞微核试验显示,蜂胶3个剂量组的微核发生率均在正常范围内,与阴性对照组比较无显著性差异(P>0.05),与阳性对照组比较差异显著(P<0.05);小鼠精子畸形试验可见,蜂胶3个剂量组的精子畸形率均在正常范围内,与阴性对照组比较无显著性差异(P>0.05),与阳性对照组比较差异显著(P<0.05)。结论蜂胶对所试菌株、小鼠体细胞及生殖细胞无诱变性。     

Antimutagenic potential of homoisoflavonoids from Muscari racemosum

The potential antimutagenic effect of the plant extract of Muscari racemosum bulbs, rich on 3-benzylidene-4-chromanones, was evaluated on three genetic model organisms. The mixture of three homoisoflavonoids was applied together with diagnostic mutagens in the Ames assay on four bacterial strains Salmonella typhimurium TA97, TA98, TA100, TA102, in the toxicity and mutagenicity/antimutagenicity assay on the yeast strain Saccharomyces cerevisiae D7, and in the simultaneous phytotoxicity and clastogenicity/anticlastogenicity assay on Vicia sativa (L.). The extract exerted antimutagenic and anticlastogenic effects due to the presence of homoisoflavonoids, which may be included in the group of natural antimutagens. This genotoxicological study suggests that homoisoflavonoids from M. racemosum (L.) owing to antimutagenic and anticlastogenic properties are of great pharmacological importance, and might be beneficial for prevention of cancer.     

Evaluation of the mutagenic and antimutagenic effects of South African plants

Dichloromethane and 90% methanol extracts of 42 South African plants were screened for mutagenicity and antimutagenicity using the Salmonella/microsome mutagenicity assay (Ames) against Salmonella typhimurium TA98 and TA100 bacterial strains in the presence and absence of metabolic activator S9. The methanol extracts from whole plants of Helichrysum simillimum, Helichrysum herbaceum and Helichrysum rugulosum indicated mutagenicity. These are the first reported tests on the mutagenicity of Helichrysum species. Six species indicated antimutagenic properties, all in the presence of S9: methanol leaf extract of Bauhinia galpinii, and dichloromethane leaf extracts of Bauhinia galpinii, Clerodendrum myricoides, Datura stramonium, Buddleja saligna, Millettia sutherlandii and Sutherlandia frutescens.     

In vitro antioxidant, antimutagenic and genoprotective activity of Rosa roxburghii fruit extract

The antioxidant properties of the fruit of the Rosa roxburghii (RR) plant have been associated with several putative health promoting effects. The possible cytotoxic, mutagenic/antimutagenic and genotoxic effects of RR fruit extract were investigated. The effect on antioxidant status and protection against induced oxidative stress were also investigated using primary rat hepatocytes. A RR fruit extract containing 45 g/L total ascorbic acid and 65 g/L total polyphenols was used in this study. Dilutions up to 0.08% (v/v) increased significantly the antioxidant status in primary rat hepatocytes. The glutathione redox state was decreased with RR treatment but was increased in Chang liver cells and MT-2 lymphoblast. No cyto- or genotoxicity were observed at levels of up to 5% (v/v) of the fruit extract. In addition, a significant protection against t-BHP induced oxidative stress was observed in primary rat hepatocytes. The Ames test revealed no mutagenic activity using the Salmonella typhimurium strains TA98, TA100 and TA102. A significant antimutagenic effect of the extract was observed against the metabolic activated mutagens 2-acetylaminofluorene and aflatoxin B1 and to a lesser extent against methyl methanesulfonate. It is concluded that these results support the associated health promoting potential of Rosa Roxburghii fruit and in particular against oxidative stress.     

Genotoxicity of Brosimum gaudichaudii measured by the Salmonella/microsome assay and chromosomal aberrations in CHO cells

The root bark of Brosimum gaudichaudii Trécul (Moraceae) is popularly used for treatment of vitiligo. In the present study the mutagenic activity of the aqueous and methanolic extract as well as of the n-butanolic fraction of this medicinal plant were evaluated using Salmonella typhimurium assays, TA100, TA98, TA102 and TA97a strains, while the clastogenic effect in Chinese hamster ovary (CHO) cells in the G(1)/S, S and G(2)/S phases of the cell cycle. The results showed mutagenic activity of the aqueous extract against TA102 in the presence of S9, and of methanolic extract, with and without metabolic activation. TA100 mutagenicity was only observed for the methanolic extract in the absence of S9. The n-butanolic fraction did not present mutagenic activity. In CHO cells only the methanolic extract induced a significant increase of chromosomal aberrations in the G(1)/S and S phases, whereas a decrease in the mitotic index was observed in the G(1)/S and G(2)/S phases. No clastogenicity was observed for the aqueous extract. The furocoumarins (psoralen and bergapten) presented in the extracts might contribute to the mutagenicity. The lower activity of the aqueous extract was probably due to the presence of smaller amount of furocoumarins compared to the methanolic extract.     

Mutagenic evaluation and chemical investigation of Byrsonima intermedia A. Juss. leaf extracts

Byrsonima intermedia is a native species of the cerrado formation (tropical American savannah). In Brazil, this plant has been used for the treatment of fever, in ulcers, as a diuretic, as antiasthmatics and in skin infections. Members of the genus Byrsonima (Malpighiaceae) are employed not only in the folk medicine but also as food to make juice, jellies and liquor. The aim of this work was to evaluate the mutagenic effects of Byrsonima intermedia, common name 'murici'. Phytochemical analysis of methanol extract furnished (+)-catechin, (-)-epicatechin, quercetin-3-O-beta-d-galactopyranoside, methyl gallate, gallic acid, quercetin-3-O-alpha-l-arabinopyranoside, amentoflavone, quercetin, quercetin-3-O-(2'-O-galloyl)-beta-galactopyranoside and quercetin-3-O-(2'-O-galloyl)-alpha-arabinopyranoside. Methanol, hydromethanol and chloroform extracts were evaluated in mutagenic assay with Salmonella typhimurium (Ames test) and mice (Micronucleus test). The methanolic extract presented signs of mutagenic activity for the strains TA98 and TA100 in the Ames assay. Mutagenicity was not observed in vivo.     

Pharmacological and phytochemical study on a Sisymbrium officinale Scop. extract

Ethnopharmacological relevance

The aerial parts of Sisymbrium officinale Scop. are commonly used to treat airway ailments, moreover in antiquity the herbal drug was reputed to possess anticancer properties. The results obtained in present work support the traditional use and the properties ascribed to Sisymbrium officinale.

Aim of the study

In order to give a scientific basis to the traditional uses of Sisymbrium officinale, this study was aimed to evaluate in vitro the myorelaxant activity, the antimicrobial properties and the antimutagenic effect of an aqueous dry extract of the aerial parts of the plant. A phytochemical characterization of the extract was also performed.

Materials and methods

The myorelaxant activity was studied against the contractions induced by carbachol, histamine and leukotriene C₄, in isolated guinea-pig trachea. The antimicrobial activity was tested against six bacteria and one yeast. The Ames test, performed by the preincubation method, was used to study the antimutagenic activity of the extract by its capability to inhibit the mutagenic effect of 2-nitrofluorene, sodium azide, methyl methanesulfonate and 2-aminoanthracene, in Salmonella typhimurium TA98, Salmonella typhimurium TA100 and Escherichia coli WP2uvrA strains. The chemical composition of the extract was analyzed by TLC and HPLC.

Results

Sisymbrium officinale showed to reduce the chemically-induced contractions of isolated guinea-pig trachea with major potency against leukotriene C₄ and histamine. The extract did not show any antibacterial activity. The Ames test showed a strong antimutagenic activity against 2-aminoanthracene, in Escherichia coli WP2uvrA and in Salmonella typhimurium TA98 strains. The phytochemical study highlighted the presence of putranjivine, the glucosinolate marker of Sisymbrium officinale, and of proline.

Conclusions

The myorelaxant activity of Sisymbrium officinale offers a scientific basis to its use in traditional medicine. The strong antimutagenic effect suggests further studies to evaluate its possible chemopreventive activity.     

戴氏虫草多糖抗突变活性的研究

目的探讨戴氏虫草菌丝体胞外水溶性多糖(CDP1)是否具有抗突变效应.方法采用Ames试验及小鼠骨髓嗜多染红细胞(PCE)微核形成试验评价不同浓度的CDP1的抗突变作用.结果CDP1在未加S9条件下,对TA97、TA98、TA100及TA102回复突变均具有不同程度的抑制作用,尤其对TA97、TA98及TA102更为明显,其最高抑制率分别达68.5%、79.5%及81.3%,且结果呈现一定的剂量-效应关系,对TA100表现较弱,但最高抑制率仍达19.8%;CDP1对环磷酰胺诱发的小鼠骨髓PCE微核发生率也有显著的拮抗作用,其最高抑制率达70.3%,且结果亦呈现剂量-效应关系.结论在本实验条件下,戴氏虫草菌丝体胞外水溶性多糖具有明显的抗突变活性.     

Assessment of mutagenicity in Parthenium hysterophorus L

The mutagenic potential of a crude extract of Parthenium hysterophorus L. was assessed in the Salmonella/microsome (Ames) assay and the mouse bone marrow micronucleus test. Results in the bacterial mutagenicity assay were negative for the five strains employed, e.g. TA 1535, TA1537, TA 98, TA 100 and TA 102, while cytotoxicity was evident in all cases at 5000 microg per plate, the highest concentration assayed. A decrease in toxicity was observed with exogenous mammalian metabolic activation (S9) or glutathione (5 micromol per plate). When mutagenicity was monitored after column chromatography fractionation of the crude, fraction 1 was mutagenic in strain TA 98 (+S9). Besides, cytotoxicity was found in fraction 5, where parthenin was eluted. The micronucleus test was negative in mice upon oral administration, at doses up to 96 mg of crude per kg. Bone marrow toxicity was not observed. The crude extract exhibited some in vitro pro-oxidant activity. It also inhibited lipid peroxidation (IC(50)=4.1 microg/ml) but failed to act as .OH scavenger.     

Antimutagenic effects of black tea (World Blend) and its two active polyphenols theaflavins and thearubigins in Salmonella assays

Almost two thirds of the world population consume tea everyday. Tea is processed differently in different parts of the world to give green (20%), black (78%) or oolong tea (2%). The antimutagenic and anticarcinogenic activities of green tea were extensively investigated compared with those of black tea. Considering the potent antimutagenic effects of green tea we recognized the need to evaluate the antimutagenic effects of black tea (World Blend Tea, Southern Tea Co., Marietta, GA) in Salmonella strains TA97a, TA98, TA100 and TA102 in preincubation tests, both with and without S9 activation. Attempts have also been made to compare the results of the tea extracts with their two active polyphenols theaflavins and thearubigins. Antimutagenicity assays were carried out in bacterial plates treated with different concentrations (1%, 2.5%, 5%, 10% and 20%) of tea extracts against known bacterial mutagens sodium azide, 4-nitro-o-phenylenediamine, cumine hydroperoxide, 2-aminofluorene and danthron. A significant decrease in the number of revertant colonies was observed in the plates treated with 1% to 20% of tea extract plus positive mutagen when compared with positive mutagen only. Both the active polyphenols theaflavins and thearubigins extracted from the black tea (World blend) also showed significant antimutagenic effects against known positive compounds in these strains. In the experiments with S9 activation, the antimutagenic effects were significantly higher. These results indicate that black tea and its two polyphenols have significant antimutagenic effects in Ames Salmonella assays.     

Antimutagenic activity of methanolic extract of Ganoderma lucidum and its effect on hepatic damage caused by benzo[a]pyrene

The antimutagenic activity of the methanolic extract of the fruiting bodies of Ganoderma lucidum (Fr.) P. Krast. occurring in South India was investigated. The activity was assayed by Ames Salmonella mutagenicity test using histidine mutants of Salmonella typhimurium tester strains, TA98, TA100 and TA102. The methanolic extract of the mushroom significantly inhibited (P<0.001) the in vitro sodium azide (NaN(3)), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and 4-nitro-o-phenylenediamine (NPD), and benzo[a]pyrene (B[a]P) induced his(+) revertants in a dose dependent manner. In vivo antimutagenic activity of extract was also assayed by determining the mutagenicity of the urine of rats administrated with B[a]P as a mutagen. The prior administration of extract markedly inhibited mutagenicity induced by B[a]P. The results indicated that the methanolic extract of Ganoderma lucidum occurring in South India possessed significant antimutagenic activity. The effect of B[a]P on hepatic enzymes, such as serum glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT) and alkaline phosphtase (ALP), were also evaluated. The extract prevented the increase of SGOT, SGPT, and ALP activities consequent to B[a]P challenge, and enhanced the levels of reduced glutathione (GSH) and activities of glutathione peroxidase (GPx), glutathione-S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT). The extract also profoundly inhibited lipid peroxidation induced by B[a]P. The results revealed that Ganoderma lucidum extract restored antioxidant defense and prevented hepatic damage consequent to the challenge by B[a]P.     

Study of the Mutagenic Activity of Extracts of the Plant Wilbrandia ebracteata

The present study was carried out to investigate the mutagenic activity of six extracts of the plant Wilbrandia ebracteata (family Cucurbitacea), one of the species found in products commercially sold as "Taiuiá'. The method for investigation was the Salmonella/microsome assay using strains TA100, TA98 and TA102 in assays carried out in the presence or absence of S9Mix as the activating system. The results indicate the absence of mutagenic activity in flavonoid and cucurbitacin-rich fractions. Signs of an increased mutagenic index were detected in the methanol fractions prepared from dried roots. We observed an increased dose response below a revertant rate, which was twice the spontaneous yield.     

Mutagenic potencies of medicinal plants screened in the ames test

Aqueous extracts of three species used in Brazilian popular medicine (Sambacus australis, Bauhnea forficata, Mimosa bimucromata) were screened for the presence of mutagenic activity in the Ames test. The extracts showed frameshift mutagenic activity after metabolization. In addition, M. bimucromata presented positive results in the TA100 strain, which detects a base pair substitution, with and without metabolization. The metabolites of B. forficata extract also showed mutagenic activity in the TA102 strain. The presence of flavonoids and tannins in the extracts may be correlated to positive mutagenic activity.     

Mutagenicity, antimutagenicity and cytotoxicity evaluation of South African Podocarpus species

Ethnopharmacological relevance

Four species of Podocarpus are used in traditional medicine both in human and animal healthcare in South Africa. In vitro pharmacological screening of leaf and stem extracts of these species exhibited potent antimicrobial, anti-inflammatory, anti-tyrosinase, anthelmintic, acetylcholinesterase inhibitory and antioxidant activities.

Aim of the study

To investigate the mutagenicity, antimutagenicity and cytotoxicity effects of leaf and stem extract of South African Podocarpus species.

Material and methods

The mutagenicity and cytotoxic effects of extracts from four species of Podocarpus were tested using the Salmonella/microsome assay with and without metabolic activation, based on the plate-incorporation method and neutral red uptake (NRU) assay respectively. Five Salmonella typhimurium tester strains; TA98, TA100, TA102, TA1535 and TA1537 were used for mutagenicity testing. The relative cytotoxicity of the extracts was assessed by determining their NI₅₀ values (50% inhibition of NRU).

Results

The extracts did not show any mutagenic effects against all the tester strains with or without metabolic activation. All extracts demonstrated a strong antimutagenic effect on the mutations induced by 4NQO, decreasing its mutagenic effect in a dose-dependent manner. Strong cytotoxic effects were exhibited by petroleum ether extracts as compared to 80% ethanol extracts. When HepG2 cells were in contact with plant extracts in an increasing concentration, slopes of NRU decreased (highest-lowest %) following a concentration-dependent pattern. For 80% ethanol extracts, the most toxic extract in terms of percentage viability was leaves of Podocarpus falcatus whereby at 0.2 mg/ml, the viability of the cells was 38.9%. Stem extract of Podocarpus latifolius was the most toxic among PE extracts, giving a percentage viability of 46.4 at 0.1 mg/ml.

Conclusion

Absence of mutagenicity does not indicate lack of toxicity, as was observed from these extracts. These findings will help in assessing the safety measures to be considered in the use of these species and also the need to determine the cytotoxic potential of these species against various forms of human cancer cells.