Foxtail activity

TFMS derivative in the presence of surfactant (cf. also Figures 2a and 2c). Thus, the loss in Foxtail activity which results from the deleterious effect of surfactant on the pa term in the Hansch equation is compensated by the improved partitioning characteristics (large Bn term) of the 4-methylsulfonyl derivative in the presence of surfactant. The net result is that the overall pre-emergence Foxtail activity is not greatly affected by Tween 80. As illustrated in Table XIII, however, this effect is only apparent since significant changes in both ir and a dependence have taken place. 

Wild Mustard activity of the 4-Cl-TFMS derivative in both the presence and absence of Tween 80 is higher than that observed for Foxtail because both r = +0.91 and v = —0.45 for this compound lie closer to their appropriate tr optima (tt0 = +0.36 (no surfactant) tr0 = —0.59 (with surfactant)) than was the case for Foxtail. Hence, the Air2 + Bw contribution for the broadleaf in both the presence and absence of surfactant is more favorable than it is for the grass. The pa contribution is also more favorable for Wild Mustard because of the high value of p for 4-substituted TFMS compounds in the presence and absence of Tween 80 (see Table XI). Thus, for the 4-Cl-TFMS derivative, both enhanced partitioning characteristics and a more favorable electronic situation (more positive pa) combine to give higher Wild Mustard than Foxtail activity. 

Free radical quenching by extracts of brown ragi was 94% while that by germinated, fermented and white ragi was 22%, 25%, and 5%, respectively. Extracts from foxtail was equally effective while extracts from rice had a free energy quenching activity of 1.8 (Sripriya et al., 1996). Mehta (2006) extracted ragi flour with methanol and added the dried powder to... 

Asharani et al. (2010) compared the antioxidant activity (measured as a-tocopherol units per gram) of methanolic extracts from different varieties of finger millet ( . coracana), little millet (P. sumatrense), foxtail millet (S. italica), and proso millet (P. miliaceum). Extracts from ragi averaged 15.3 0.6 while those of little millet, foxtail millet, and proso millet were 4.7 1.1,5.0 0.4, and 5.1 0.8, respectively. The total tocopherols in these millets were 4.1 0.2,1.3 0.2,1.2 0.008, and 3.6 0.1 mg/lOOg flour. 

Indolin-2-on-3yl)hydrazino-5,6,7,8-tetrahydrobenzo[fe]thieno[2,3-d]-pyrimidine 185 showed 10-20% herbicidal activity against pigweed, velvet leaf, red millet, green foxtail, and soya bean (81JHC1277). 

Evaluation of TFMS Herbicidal Activity. The herbicidal potency of the 15 substituted TFMS compounds was rated after a 21-day test period on a 0-100% kill scale. Herbicidal test data were collected for two grass species (Foxtail, Cheat Grass) and a broadleaf weed (Wild Mustard) in the presence and absence of 0.1% (w/v) Tween 80. Since the tests... 

Separation of TFMS Herbicides into Meta- and Para-Substituted Series. In our initial correlations, herbicidal activity data from Table VII for each weed type in the presence and absence of Tween 80 were fitted to the appropriate form of Equations 7-9. A typical result is illustrated by the stepwise regression obtained for Foxtail grass in the absence of surfactant ... 

Methylthio TFMS Derivatives. Data for the meta- and para-substituted methylthio TFMS derivatives (3-SCH3, 4-SCH3) were not included in Hansch structure—activity correlations for the several weed types. This omission was a result of our noting that when herbicidal data for the methylthio derivatives were included in fits, much poorer Hansch correlations were obtained. This was true whether or not the TFMS compounds were separated into meta- and para-derivatives for fitting purposes. It was also true for all weed types examined, in the presence and absence of surfactant. A typical example of the improvement in statistical parameters effected by omitting methylthio points from the data pool is illustrated by the following Hansch correlation of TFMS activity on Foxtail grass in the presence of surfactant. 

Figure 2a. Three-dimensional perspective plot of the Hansch equation describing pre-emergence activity of 4-sub stituted TFMS herbicides on Foxtail grass (no Tween 80 present)...

TFMS Herbicides in the Presence of 0.1% Tween 80. Let us now turn our attention to the effect that the addition of a small amount of Tween 80 to the TFMS herbicidal formulations has on the shape and orientation of the activity plots for Foxtail and Wild Mustard. Considering first the 4-substituted derivatives and comparing Figure 2a with 2c for Foxtail and Figure 3a with 3c for Wild Mustard, we note that the addition of surfactant in both cases has two obvious consequences ... 

In addition to the pronounced effects of surfactant on ir discussed above, addition of Tween 80 to 4-TFMS herbicidal formulations produces smaller changes in the a dependence (cf. Figures 2a and 2c for Foxtail and 3a and 3c for Wild Mustard). In Table XI, this a dependence appears as a slight decrease in the parameter coefficient p for 4-TFMS activity on Wild Mustard and as a large decrease in p for 4-TFMS activity on Foxtail when surfactant is added. Comparing Figures 2a and 2c for Foxtail, this decrease in p manifests itself as a decrease in slope of the activity surface in the positive a direction. For substituents with large positive o- values,... 

From Table XI, note that the tt optimum for both 3- and 4-substituted TFMS series members acting on Foxtail grass in the presence of surfactant is 7t0 = —0.77. Examination of Figures 2c and 2d indicates, however, that gross differences in the herbicidal activity surfaces for the meta- and para-TFMS series exist. On this basis, it would appear that coincidence of tt0 values for 3- and 4-substituted series is not a sufficient condition for assuming that modes of herbicidal action for the two series are also identical. 

Finally, Table XII showed that for both 3- and 4-substituted TFMS series, poorer correlations were obtained when herbicidal data obtained in the presence and absence of Tween 80 for a given series acting on a particular weed type were pooled and fitted simultaneously. Comparing the appropriate surface plots in Figures 2-3 for Foxtail and Wild Mustard, it is evident that poor correlations of the pooled data would have been obtained. The very different graphical curve shapes obtained for each TFMS series in the presence and absence of Tween 80 illustrate why correlations of the pooled data produced poor structure-activity correlations. 

As an illustration of the use of the final Hansch relationships in Table XI in explaining biological activity differences between individual TFMS series members, we will examine the activity of 4-S02CH3-TFMS and 4-C1-TFMS against Foxtail, Wild Mustard, and Cheat Grass. Table XIII gives values of the individual terms in the Hansch equations of Table XI which are appropriate to the action of each herbicide on the three weed types. At a later point, we also examine the activity of 2,4-di-Cl- and 2,4-di-F-TFMS derivatives as predicted by the Hansch relationships in Table XI. 

S02CH3-TFMS and 3-S02CH3-TFMS derivatives as they do in the Foxtail surfactant case (see Table XV). Although methylthio-TFMS derivatives might possibly be protected from in vivo oxidation by Tween 80 absorbed by the Wild Mustard seeds (micelle formation), a process of this type would not be observable experimentally since slower ratedetermining partitioning events control the overall herbicidal activity as previously explained. 

Of considerable interest also is the effect that surfactant has on the position of the various tt optima for the Foxtail and Wild Mustard activity surfaces (see Figures 2 and 3). Table XI shows that 7r0 for the para-TFMS derivatives acting on Foxtail in the absence of surfactant is tt0 = +0.16, while in the presence of Tween 80 it is shifted to tt/ = —0.77. Referring now to Figure 6, note that the 7r0 value for the para substituents in the non-surfactant case falls between the tt values for the 4-F- and 4-OCH3—TFMS substituents. In the presence of surfactant, the tt optimum is shifted toward more hydrophilic substituents and is now located between the 7r values of the 4-OCH3- and 4-SOjCH3- substituents. 

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