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Anticandidal effect of Ocimum sanctum essential oil and its synergy with fluconazole and ketoconazole.

ABSTRACT

Holy basil, Ocimum sanctum (L.) is time-honored for its medicinal properties; however its antimicrobial characteristics are used only in 'Ayurvedic medicines'. Attention has been drawn to antifungal activity and a possible synergistic antifungal effect of Ocimum sanctum essential oil (OSEO) and established azole antimycotics-fluconazole and ketoconazole. To put forward this approach, antifungal activity has been assessed in seventy four fluconazole-sensitive and sixteen fluconazole-resistant Candida isolates. Hemolytic activity on human erythrocytes was also studied to rule out the possibility of allied additional cytotoxicity. The observed selectively fungicidal characteristics signify a promising candidature of O. sanctum essential oil as an antifungal agent in combinational treatments for candidosis.

[C] 2010 Elsevier GmbH. All rights reserved.

ARTICLE INFO

Keywords: Ocimum sanctum Essential oil Candida Fluconazole Ketoconazole

Introduction

Studies have been carried out from long time on essential oils and natural extracts, and have proved that the natural products have highly momentous antibiotic properties (Khan et al., 2010; Ahmad et al., 2010; Pinto et al., 2006). More recently, azole antifungal compounds, which have excellent efficacy-toxicity profiles, have emerged as the principal drugs used in the treatment of candidal infections in non-neutropenic patients. The most widely used drug in both the treatment and prevention of candidiasis is fluconazole (FLC) (Vanden Bossche, 1985). However, in recent years, prolonged use of FLC has contributed to the development of drug resistance in C. albicans and other species (Sanglard et al., 2003). One selective pressure contributing to the emergence of drug resistance is the fungistatic rather than fungicidal character of azole action (Uppuluri et al., 2008). Improvements in the efficacy of antifungal drug therapy may be achieved by using combination therapy (Tariq et al., 1995). Thus, new therapeutic strategies are necessary. Ocimum sanctum L. held sacred by Hindus, distributed and cultivated widely around the world is used in herbal medicine for the management of various disease conditions (Sethi et al., 2003; Nweze and Eze, 2009). We evaluated antifungal activity and synergistic effects of the Ocimum sanctum essential oil, with FLC and ketoconazole by CLSI microdilution method, agar disc diffusion and broth microdilution checkerboard assay (Canton et al., 2005).

Materials and methods

Methyl chavicol from Aldrich (USA), linalool from Aldrich (Germany), carvone from SAFC (USA), and limonene from Himedia (India) were purchased, whereas all inorganic chemicals were of analytical grade and were procured from E. Merck (India).

Samples (leaves and stems) were collected from local farms of Faridabad and Noida, India and identified at Department of Biosciences, JMI. Once dried, the samples were subject to hydro-distillation carried out at Pravek Kalp Herbal Products, Noida, India by means of a Clevenger apparatus (Buchi). The essential oil obtained was dehydrated over anhydrous sodium sulphate and stored at 4 [degrees]C after filtration. The composition of essential oil was analysed by GC-MS using Shimadzu 2010 gas chromatograph fitted with AB-Wax Column. Helium was used as the carrier gas. 0.1 [mu]l sample was injected with splitless mode. The chemical components from the essential oil were identified by comparing the retention times of chromatographic peaks with those of authentic compounds using the WILEY8.LIB and NIST05s.LIB.

Fungal strains

Fungal strains classified in Table 2 have been used in the present study.

Assessment of the MIC, FIC index

The Minimum Inhibitory Concentration (MIC) defined as the lowest concentration of test entity that causes 90% decrease in absorbance (MIC90) compared with that of the control, was determined in vitro by NCCLS, document M27--A2, 2002. The broth microdilution checkerboard method was performed by using the fractional inhibitory concentration index (FICI), which is defined as the sum of the MIC of each drug when used in combination divided by the MIC of the drug when used alone. Synergy and antagonism were defined by FICIs of [less than or equal to]0.5 and >4, respectively. A FICI result of >0.5 but [less than or equal to]4 was considered indifferent (Canton et al., 2005).

Disk diffusion assays

Strains were inoculated into liquid YPD medium and grown overnight at 37[degrees]C. The cells were then pelleted, and washed three times with distilled water. Approximately [10.sup.5] cells/ml was inoculated in molten agar media at 42[degrees]C and poured into 100-mm-diameter petriplates. Filter discs were kept on solid agar and test oil was spotted on the disk. Varying concentrations of test oil dissolved in 10% DMSO, or in combination with azole, or solvent control (10% DMSO) were pipetted onto 4-mm-diameter filter disk. 100 mg/ml of azole was also implied on the disks to serve as negative control. The diameter of zone or inhibition was recorded in millimeters after 48 h and was compared with that of control.

Hemolytic activity

Hemolytic activity of O. sanctum essential oil on human red blood cells was performed in vitro as described earlier (Ahmad et al., 2010) and hemolysis percentage was calculated by following equation:

% hemolysis = [([A.sub.450] of test compound treated sample--[A.sub.450] of buffer treated sample)/([A.sub.450] of 1% Triton X-100 treated sample--[A.sub.450] of buffer treated sample)] x 100%.

Results and discussion

The qualitative and quantitative composition of the oil analysed is shown (compounds [greater than or equal to] 1%) in Table 1. Fifty-three components representing 100% of the oil were identified. The oil was characterized by high amounts of methyl chavicol (44.63%), and linalool (21.84%). Although the Indian O. sanctum is reported to be a eugenol chemotype (Prakash and Gupta, 2005), but seasonal variations are seen typically in the composition of essential oil (Rajeshwari, 1992; Laskar and Majumdar, 1988). In addition to this, recent studies show linalool (Zheljazkov et al., 2008; Khan et al., 2010), methyl eugenol (Raseetha et al., 2009) and methyl chavicol (Zheljazkov et al., 2008) as lead molecules in the composition of O. sanctum essential oil. Essential oil used in the present study, however, represents the methyl chavicol chemotype (Table 1). Evaluation of MIC showed that the oil was active in vitro against all the tested strains (Table 2), with MIC range from 0.1[mu]l/ml to 0.5 [mu]l/ml against Candida. Nevertheless, it is reasonable to speculate that the activity of this oil can be related to the presence of its lead constituents - methyl chavicol, linalool, limonene carvone and [alpha]-caryophyllene. D-Limonene (MIC = 750-1000[mu]g/ml), [alpha]-caryophyllene (MIC = 500-600[mu]g/ml) and carvone (MIC = 250-350 [mu]g/ml) did not however show considerable activity towards standard ATCC strains (C. albicans ATCC 90028, C. tropicalis ATCC 750 and C. glabrata ATCC 90030), and therefore their input can be assumed to be petite to the oil's activity. Methyl chavicol and linalool were found to be the most active constituents (Table 2) of O. sanctum essential oil, with MIC values ranging from 125 to 200 [mu]g/ml and 200 to 250 [mu]g/ml, respectively. Nevertheless, methyl chavicol proved to be more active against all Candida strains, in a similar manner to the essential oil. It is to be noted that isolates intrinsically resistant to fluconazole also show sensitivity to essential oil (Table 2B).
Table 1

Major constituents of the essential oil of O. sanctum after GC-MS
analysis.

Compound R. Time Area%

D-Limonene 9.932 4.39
Linalool 19.896 21.84
[alpha]-Famesene 21.197 1.62
Caryophyllene 21.676 1.4
Menthol 22.685 1.76
Methyl Chavicol 23.897 44.63
[alpha]-Citral 25.425 1.26
Carvone 25.627 6.31
[alpha]-Caryophyllene 26.55 3.3
p-Methoxycinnamaldehyde 50.284 1.12


The fractional inhibitory concentration (FIC) indices of both OSEO combined with FLC and ketoconazole (KETO) against all FLC sensitive Candida isolates studied, calculated from the checkerboard microtiter assay were ranged from 0.24 to 0.53 and 0.25 to 0.54 respectively, indicating significant synergism (Table 2). OSEO alone and in combination with the antifungal drugs exhibited intense growth inhibition.
Table 2

Antifungal and synergistic activity (MIC and FICI) of the essential oil
of O. sanctum (L.) and its major compounds against (A) fluconazole-
sensitive standard and clinical isolates; (B) fluconazole-resistant
clinical isolates.

Isolates MIC FLC MIC KETO MIC OSEO (a) MIC MET MIC LIN (b)
 (b) (b) CHAV (b)

(A)

C. albicans 3 5 0.25 200 250
ATCC 90028

C. albicans 3 5 0.2 150 200
ATCC 10261

C. albicans 4 6 0.2 200 250
ATCC 44829

C. tropicalis 3 5 0.15 125 200
ATCC 750

C. glabrata 4 5 0.2 200 250
ATCC 90030

C. albicans 5.5 4 0.2 150 250
177

C. tropicalis 5 5 0.1 125 200
105

C. tropicalis 7.5 5 0.1 125 200
196

C. albicans 6 5 0.15 150 200
2281

C. albicans 6 5 0.1 125 200
2323

C. albicans 6 4 0.15 150 200
2367

C. albicans 6 5 0.15 150 200
2427

C. albicans 6 5 0.1 125 200
2434

C. albicans 6 5 0.1 125 200
2437

C. albicans 6 5 0.1 125 200
2508

C. albicans 5.5 4 0.1 125 200
2642

C. albicans 5.5 4 0.2 150 250
2643

C. albicans 5.5 4 0.1 125 200
2764

C. albicans 5.5 4 0.1 125 200
2779

C. albicans 5.5 4 0.1 125 200
2780

C. albicans 5.5 4 0.1 125 200
2781

C. albicans 5.5 4 0.1 125 200
2784

C. albicans 5.5 4 0.1 125 200
2865

C. albicans 5.5 4 0.2 200 250
2883

C. albicans 7 4 0.15 150 200
2889

C. albicans 7 4 0.1 125 200
2920

C. albicans 5.75 4 0.1 125 200
2938

C. albicans 6.75 4 0.2 125 200
3021

C. albicans 6.75 5 0.1 125 200
3031

C. albicans 6.75 5.5 0.24 200 250
3034

C. albicans 5 5 0.1 125 200
3035

C. albicans 5 4 0.2 175 250
3036

C. albicans 5 5 0.1 125 200
3043

C. albicans 4 5 0.1 125 200
3054

C. albicans 4 5 0.15 200 200
3070

C. albicans 4 5 0.15 150 200
3078

C. albicans 4 5 0.15 150 200
3140

C. albicans 4 5 0.1 125 200
3143

C. albicans 2.5 5 0.1 125 200
3253

C. glabrata 4 6 0.2 200 200
2994

C. glabrata 3 6 0.15 200 200
3147

C. glabrata 2.5 6 0.2 200 200
3214

C. glabrata 4 6 0.24 200 250
3249

C. 5 9 0.25 200 250
parapsilosis
2559

C. 7.5 9 0.3 200 250
parapsilosis
2615

C. tropicalis 7.5 5 0.1 125 200
2029

C. tropicalis 5 5 0.1 125 200
2356

C. tropicalis 5 5 0.1 125 200
2366

C. tropicalis 5 5 0.2 125 200
2442

C. tropicalis 5 5 0.2 125 200
2480

C. tropicalis 5 5 0.2 125 200
2509

C. tropicalis 5 5 0.2 125 200
2557

C. tropicalis 7.5 5 0.2 125 200
2627

C. tropicalis 5 5 0.2 125 200
2768

C. tropicalis 5 6 0.2 125 200
2778

C. tropicalis 5 6 0.15 200 200
2803

C. tropicalis 5 4 0.1 125 200
2804

C. tropicalis 5 6 0.1 125 200
2833

C. tropicalis 5 6 0.1 125 200
2852

C. tropicalis 7.5 6 0.1 125 200
2854

C. tropicalis 7.5 5.5 0.1 125 200
2858

C. tropicalis 5 5.5 0.1 125 200
2863

C. tropicalis 5 5.5 0.1 125 200
2881

C. tropicalis 5 4 0.15 200 200
2960

C. tropicalis 5 5 0.15 200 200
3013

C. tropicalis 5 5 0.15 200 200
3056

C. tropicalis 5 4 0.2 125 200
3079

C. tropicalis 7.5 4 0.2 125 200
3167

C. tropicalis 7 5 0.2 200 250
3191

C. tropicalis 5 5 0.2 125 200
3211

C. tropicalis 7.5 5 0.2 125 200
3219

C. tropicalis 7.5 5 0.2 125 200
3220

C. tropicalis 7.5 5 0.2 125 200
3240

C. tropicalis 7.5 5 0.2 125 200
3261

Clinical isolates of Candida resistant to FLC
([greater than or equal to]64 [mu]g/ml)

(B)

C. albicans 0.2 150 250
3001

C. albicans 0.2 150 250
3048

C. albicans 0.2 150 250
3068

C. albicans 0.2 175 250
3087

C. albicans 0.15 125 200
3178

C. glabrata 0.2 175 250
2993

C. glabrata 0.2 150 250
3080

C. krusei 0.35 200 250
191

C. krusei 0.3 175 250
139

C. krusei 0.3 200 250
337

C. krusei 0.3 200 250
342

C. 0.35 200 250
parapsilosis
218

C. 0.3 200 250
parapsilosis
2918

C. 0.5 150 250
parapsilosis
3277

C. tropicalis 0.2 150 250
321

C. tropicalis 0.2 150 250
341

Isolates FICI-OSEO Interpretation FICI-OSEO + Interpretation
 + FLC KETO

(A)

C. albicans 0.48 SYN 0.42 SYN
ATCC 90028

C. albicans 0.47 SYN 0.41 SYN
ATCC 10261

C. albicans 0.48 SYN 0.50 SYN
ATCC 44829

C. tropicalis 0.47 SYN 0.46 SYN
ATCC 750

C. glabrata 0.48 SYN 0.36 SYN
ATCC 90030

C. albicans 0.47 SYN 0.56 IND
177

C. tropicalis 0.49 SYN 0.49 SYN
105

C. tropicalis 0.46 SYN 0.49 SYN
196

C. albicans 0.63 IND 0.49 SYN
2281

C. albicans 0.93 IND 0.52 SYN
2323

C. albicans 0.63 IND 0.71 IND
2367

C. albicans 0.29 SYN 0.49 SYN
2427

C. albicans 0.43 SYN 0.42 SYN
2434

C. albicans 0.53 SYN 0.59 IND
2437

C. albicans 0.43 SYN 0.49 SYN
2508

C. albicans 0.42 SYN 0.45 SYN
2642

C. albicans 0.27 SYN 0.30 SYN
2643

C. albicans 0.32 SYN 0.35 SYN
2764

C. albicans 0.49 SYN 0.45 SYN
2779

C. albicans 0.49 SYN 0.45 SYN
2780

C. albicans 0.49 SYN 0.46 SYN
2781

C. albicans 0.49 SYN 0.46 SYN
2784

C. albicans 0.49 SYN 0.45 SYN
2865

C. albicans 0.24 SYN 0.40 SYN
2883

C. albicans 0.40 SYN 0.38 SYN
2889

C. albicans 0.47 SYN 0.45 SYN
2920

C. albicans 0.48 SYN 0.45 SYN
2938

C. albicans 0.27 SYN 0.25 SYN
3021

C. albicans 0.37 SYN 0.35 SYN
3031

C. albicans 0.28 SYN 0.25 SYN
3034

C. albicans 0.38 SYN 0.33 SYN
3035

C. albicans 0.28 SYN 0.44 SYN
3036

C. albicans 0.38 SYN 0.33 SYN
3043

C. albicans 0.50 SYN 0.43 SYN
3054

C. albicans 0.43 SYN 0.36 SYN
3070

C. albicans 0.43 SYN 0.36 SYN
3078

C. albicans 0.37 SYN 0.50 SYN
3140

C. albicans 0.40 SYN 0.53 SYN
3143

C. albicans 0.34 SYN 0.52 SYN
3253

C. glabrata 0.33 SYN 0.41 SYN
2994

C. glabrata 0.28 SYN 0.51 SYN
3147

C. glabrata 0.30 SYN 0.25 SYN
3214

C. glabrata 0.32 SYN 0.28 SYN
3249

C. 0.30 SYN 0.26 SYN
parapsilosis
2559

C. 0.36 SYN 0.35 SYN
parapsilosis
2615

C. tropicalis 0.36 SYN 0.36 SYN
2029

C. tropicalis 0.47 SYN 0.46 SYN
2356

C. tropicalis 0.27 SYN 0.46 SYN
2366

C. tropicalis 0.47 SYN 0.36 SYN
2442

C. tropicalis 0.49 SYN 0.39 SYN
2480

C. tropicalis 0.47 SYN 0.37 SYN
2509

C. tropicalis 0.47 SYN 0.37 SYN
2557

C. tropicalis 0.46 SYN 0.38 SYN
2627

C. tropicalis 0.49 SYN 0.40 SYN
2768

C. tropicalis 0.49 SYN 0.43 SYN
2778

C. tropicalis 0.42 SYN 0.42 SYN
2803

C. tropicalis 0.37 SYN 0.46 SYN
2804

C. tropicalis 0.47 SYN 0.46 SYN
2833

C. tropicalis 0.47 SYN 0.46 SYN
2852

C. tropicalis 0.46 SYN 0.48 SYN
2854

C. tropicalis 0.46 SYN 0.46 SYN
2858

C. tropicalis 0.47 SYN 0.47 SYN
2863

C. tropicalis 0.47 SYN 0.46 SYN
2881

C. tropicalis 0.34 SYN 0.53 SYN
2960

C. tropicalis 0.34 SYN 0.54 SYN
3013

C. tropicalis 0.32 SYN 0.52 SYN
3056

C. tropicalis 0.47 SYN 0.54 SYN
3079

C. tropicalis 0.46 SYN 0.48 SYN
3167

C. tropicalis 0.31 SYN 0.60 IND
3191

C. tropicalis 0.57 IND 0.57 IND
3211

C. tropicalis 0.46 SYN 0.49 SYN
3219

C. tropicalis 0.56 IND 0.57 IND
3220

C. tropicalis 0.46 SYN 0.44 SYN
3240

C. tropicalis 0.26 SYN 0.39 SYN
3261

(a) MIC expressed in [mu]l/ml (v/v).
(b) MIC expressed in [mu]g/ml (w/v).
MET CHAV, methyl chavicol; LIN, linalool; ANT, antagonism; IND,
indifference; SYN, synergism.


All the fluconazole-susceptible and -resistant Candida isolates showed high degree of sensitivity as is evident from large inhibition zone (Fig. 1). Index of sensitivity defined as

[FIGURE 1 OMITTED]

Diameter of inhibition zone (mm)/Concentration (mg/ml) = Clearing (mm)/(mg/ml)

is greatest (7.911 [+ or -]0.213) for OSEO in combination with ketoconazole against clinical isolates. The sensitivity index for all the strains with OSEO alone and in combination with the antifungal drugs is shown in Table 3. Fluconazole-resistant isolates (Fig. 1F) show more sensitivity to the combination of fluconazole and essential oil than essential oil of O. sanctum alone.
Table 3

Sensitivity index for all the strains with OSEO alone and in
combination with the antifungals fluconazole and ketoconazole.

Isolates Sensitivity Index

 OSEO Fluconazole

Standard 1.435 [+ or -] 0.156 2.7643 [+ or -] 0.216
Clinical 1.741 [+ or -] 0.213 2.4791 [+ or -] 0.283
Resistant 1.713 [+ or -] 0.217 0.0153 [+ or -] 0.017

Isolates Sensitivity Index

 Ketoconazole OSEO + Fluconazole

Standard 2.796 [+ or -] 0.209 7.496 [+ or -] 0.452
Clinical 2.701 [+ or -] 0.193 7.831 [+ or -] 0.347
Resistant 0 [+ or -] 0 6.248 [+ or -] 0.118

Isolates Sensitivity Index

 OSEO + Ketoconazole

Standard 7.506 [+ or -] 0.227
Clinical 7.511 [+ or -] 0.213
Resistant 7.118 [+ or -] 0.201


Synergism of natural products and antibiotics is a thrust area of phytomedicinal research, developing novel prospectives of phytopharmaceuticals (Wagner and Ulrich-Merzenich, 2009). The synergism of plant derived compounds and antibiotics has been elaborated previously against infectious diseases (Hemaiswarya et al., 2008), and also against Candida (Han. 2007). There has been reported a similar synergistic effect of essential oils and antifungal (Amphotericin B) against Candida (Rosato et al., 2008), the present study however explore azoles--a major class of antifungal in clinical practices, against a wide variety of Candida isolates. Our findings suggest options for expanding the utility of O. sanctum essential oil as antifungal agent.

We demonstrate that essential oil of O. sanctum is an effective antifungal agent (as is further evident from disc diffusion assay), that inhibits FLC sensitive Candida species (such as C. albicans, C. tropicalis, C. parapsilosis), but also FLC-resistant C. albicans, C. tropicalis isolates; and C. krusei and C. glabrata, which are intrinsically resistant to FLC or whose resistance is easily inducible. Out of seventy four strains studied, with the combination blend of five strains with FLC and six with KETO showed indifference (Table 2).

The in vitro hemolytic assay is a possible screening tool for gauging in vivo toxicity to host cells (Christie et al., 2007). The comparative study of OSEO with the conventional antifungals indicates that OSEO is significantly less cytotoxic (Fig. 2). 2 [mu]l/ml. OSEO showed only 5.1% hemolysis while as amphotericin B at this concentration showed 100% hemolysis. At the MIC values of OSEO and FLC, 0% and 19.3% hemolysis was observed.

[FIGURE 2 OMITTED]

From the data above, we can conclude that OSEO besides being selectively cytotoxic, shows potent in vitro antifungal effects against Candida isolates, including FLC-resistant and FLC-susceptible Candida strains, when combined with FLC or KETO. We have shown that the combination fluconazole/ketoconazole-O. sanctum essential oil administered against the fungal strains under consideration is likely to augment the efficiency of these two azoles. Future research based on animal models, may resolve in vivo efficacy of O. sanctum essential oil.

Acknowledgements

Authors wish to thank Dr. Malini R. Capoor, Associate Professor, Department of Microbiology, Vardhman Mahavir Medical College and Safderjung Hospital, New Delhi, India for providing some clinical isolates of Candida. This work was supported by University Grants Commission, India (Grant No. 33-223/2007) to Dr. L.A. Khan and Dr. N. Manzoor.

References

Ahmad, A., Khan, A., Manzoor, N., Khan, LA., 2010. Evolution of ergosterol biosynthesis inhibitors as fungicidal against Candida. Microb. Pathog. 48, 35-41.

Canton, E., Peman, J., Gobernado, M., Viudes, A., Espinel, I.A., 2005. Synergistic activities of fluconazole and voriconazole with terbinafine against four Candida species determined by checkerboard, time-kill, and etest methods. Antimicrob. Agents Chemother. 49 (4), 1593-1596.

Christie, M.S., Kenneth, L.R., David, B.W., 2007. Assessing toxicity of fine and nanoparticles: comparing in vitro measurements to in vivo pulmonary toxicity profiles. Toxicol. Sci. 97 (1), 163-180.

Han, Y., 2007. Synergic effect of grape seed extract with amphotericin B against disseminated candidiasis due to Candida albicans. Phytomedicine 14, 733-738.

Hemaiswarya, Sh., Kruthiventi, A.K., Doble, M., 2008. Synergism between natural products and antibiotics against diseases. Phytomedicine 15, 639-652.

Khan, A., Ahmad, A., Manzoor, N., Khan, L.A., 2010. Antifungal activities of Ocimum sanctum essential oil and its lead molecules. Nat. Prod. Commun. 5 (2), 345-349.

Laskar, S., Majumdar, S.G., 1988. Variation of major constituents of essential oil of the leaves of Ocimum Sanctum Linn. J. Indian Chem. Soc. 65, 301-302.

Nweze, E.I., Eze, E.E., 2009. Justification for the use of Ocimum gratissimum L. in herbal medicine and its interaction with disc antibiotics. BMC Complement. Altern. Med. 28, 9-37.

Pinto, E., Pina-Vaz, C., Salgueiro, L., Goncalves, M.J., Costa-de-Oliveira, S., Cavaleiro, C., Palmeira, A., Rodrigues, A., Martinez-de-Oliveira, J., 2006. Antifungal activity of the essential oil of Thymus pulegioides on Candida, Aspergillus and dermatophyte species. J. Med. Microbiol. 55, 1367-1373.

Prakash, P., Gupta, N., 2005. Therapeutic uses of Ocimum Sanctum Linn. (Tulsi) with a note on Eugenol and its pharmacological actions: a short review. Indian J. Physiol. Pharmacol. 49 (2), 125-131.

Rajeshwari, S., 1992. Ocimum sanctum. The Indian home remedy. Current Medical Scene, Bombay Central, Bombay.

Raseetha, V.S., Cheng, S.F., Chuah, C.H., 2009. Comparative study of volatile compounds from genus Ocimum. Am. J. Appl. Sci. 6 (3), 523-528.

Rosato, A., Viali. C., Gallo, D., Millillo, M.A., Mallamaci, R., 2008. The inhibition of Candida species by selected oils and their synergism with amphotericin B. Phytomedicine 15, 635-638.

Sanglard, D., Ischer, F., Parkinson, T., Falconer, D., Bille, J., 2003. Candida albicans mutations in the ergosterol biosynthetic pathway and resistance to several antifungal agents. Antimicrob. Agents Chemother. 47, 2404-2412.

Sethi, J., Sood, S., Seth, S., Thakur, A., 2003. Protective effect of Tulsi (Ocimum sanctum) on lipid peroxidation in stress induced by anemic hypoxia in rabbits. Indian J. Physiol. Pharmacol. 47, 115-119.

Tariq, V.N., Scott, E.M., McCain, N.E., 1995. Use of decimal assay for additivity to demonstrate synergy in pair combinations of econazole, nikkomycin Z, and ibuprofen against C. albicans in vitro. Antimicrob. Agents Chemother. 39, 2615-2619.

Uppuluri, P., Nett, J., Heitman, J., Andes, D., 2008. Synergistic effect of calcineurin inhibitors and fluconazole against Candida albicans biofilms. Antimicrob. Agents Chemother. 52, 1127-1132.

Vanden Bossche, H., 1985. Biochemical targets for antifungal azole derivatives: hypothesis on the mode of action. Curr. Top. Med. Mycol. 1, 313-351.

Wagner, H., Ulrich-Merzenich. G., 2009. Synergy research: approaching a new generation of phytopharmaceuticals. Phytomedicine 16, 97-110.

Zheljazkov, V.D., Cantrell, C.L., Tekwani, B., Khan, S.I., 2008. Content, composition, and bioactivity of the essential oils of three basil genotypes as a function of harvesting. J. Agric. Food Chem. 56, 380-385.

K. Amber (a), (1), A. Aijazal (a), (1), X. Immaculata (b), K.A. Luqman (a), M. Nikhat (a), *

(a) Department of Biosciences, Jamia Milla Islamia, New Delhi, India

(b) Department, of Microbiology, All India Institute of Medical Sciences, New Delhi, India

* Corresponding author.

E-mail address: nikhatmanzoor@yahoo.co.in (M. Nikhat).

(1) Amber Khan and Aijaz Ahmad have contributed equally to this study.

0944-7113/$ - see front matter [C] 2010 Elsevier GmbH. All rights reserved.

doi:10.1016/j.phymed.2010.02.012
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Author:Amber, K.; Aijaz, A.; Immaculata, X.; Luqman, K.A.; Nikhat, M.
Publication:Phytomedicine: International Journal of Phytotherapy & Phytopharmacology
Article Type:Report
Geographic Code:9INDI
Date:Oct 1, 2010
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