Study on altitudinal variation in phenylpropanoid rich essential oils from rhizomes of sweet flag (Acorus calamus l.) with pesticidal activities
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Date
2022-08
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G. B. Pant University of Agriculture and Technology, Pantnagar
Abstract
The objectives of the present research study were to investigate chemical composition and pesticidal activity of from A. calamus under the title “Study on Altitudinal Variation in Phenylpropanoid Rich Essential Oils from Rhizomes of Sweet Flag (Acorus calamus L.) with Pesticidal Activities”. The plants were collected from Munsyari (30.07150 N & 80.23730 E), Pantnagar (29.02290 N & 79.48790 E) and Assam (26.71770 N & 94.24310 E) India, in the month of August 2021 to October 2021. The essential oils of fresh rhizomes part of the collected plant materials were extracted by hydrodistillation using Clevenger apparatus with % yield of 0.5%-0.7% (v/w) and were designated as ACAREO (Acorus calamus Assam rhizomes essential oil), ACMREO (Acorus calamus Munsyari rhizomes essential oil) and ACPREO (Acorus calamus Pantnagar rhizomes essential oil).The essential oils were analysed for its phytochemical study and various pesticidal activities viz: nematicidal, herbicidal and insecticidal activity. In the present research work different combinations of Acorus calamus essential oils viz. AC(A:M)REO, AC(P:M)REO, AC(A:P)REO and AC(A:M:P)REO in the ratio of 1:1 were also studied for their synergistic/antagonistic effects. β–asarone was the chemical marker for different altitudinal collection with varying percentage. Its contribution was higher in ACMREO (85.8%) compared to ACPREO and ACAREO which contains 74.3% and 62.6% respectively. Although some major constituents such as (Z)-methyl- isoeugenol, β-trans-ocimene were present in all the Acorus calamus essential oils in varing amount. 6-epishyobunone, (E)- isoelemicin, isoshyobunone present only in ACAREO and ACMREO but completely missing in ACPREO. The other compounds like (Z)- asarone (4.00%) were present only in ACAREO, α-asarone (2.3%), dehydroxy-isocalamendiol (1.9%), shyobunone (5.4%) and Z-isoelemicin (4.2%) only in ACPREO. In term of class composition ACMREO was dominated over ACPREO and ACAREO in phenylpropanoid content. All the oils exhibited dose dependent in-vitro nematicidal activity against Meloidogyne incognita, as indicated by different IC50 values and LC50 values. It was found that highest IC50 was observed in ACAREO(0.041%) and lowest in AC(A:M:P)REO (0.004%) for egg hatching activity and in terms of LC50 value highest value was shown by ACAREO (0.26%) and lowest for AC(A:M:P)REO(0.13%). It was observed that ACMREO exhibited more mortality over ACPREO and ACAREO at different concentration (0.005%-0.10%) and in combination AC(A:M:P)REO was found to be more effective. Highest % inhibition was shown in ACMREO, lowest in AC(A:P)REO for egg hatching activity. Insecticidal activity against Lipaphis erysimi and Selepa celtis was highest in ACAREO (95.6% and 84.5%) respectively in terms of % average mortality. In terms of lethal dose concentration (LC50) it was least in AC(A:M:P)REO with 56.7 ppm and 60.7 ppm against Lipaphis erysimi and Selepa celtis respectively. The oils were assessed for herbicidal activity in terms of inhibition of seed germination, coleoptile growth of shoot and root. Maximum 89.7% seed germination activity was found in ACMREO compared to other samples. The percent root and shoot growth inhibition was calculated, in which AC(A:M:P)REO gave better results with 92.0% and 76.7% values for root and shoot growth inhibition at 1000 ppm concentration.