MSc

Neelamari (Indigofera tinctoria L.) belonging to the family Fabaceae, is
a widely used medicinal crop due to its properties. The main use of the
Neelamari leaves is in the preparation of Neelibhrngadi Taila which is an
Ayurvedic formulation known for its hair tonic property. The other important
ingredients of the Neelibhrngadi Taila are Amla, Eclipta alba, Cardiospermum
halicacabum, etc. The availability of Neelamari leaves restricted to a particular
season does not always coincide with the season of Amla, which may result in a
setback in the production of Neelibhrngadi Taila. In this context, the present
investigation “Postharvest studies in Neelamari (Indigofera tinctoria L.)” was
taken up to study the effect of harvesting stage and post-harvest storage on yield
and quality of leaves. The effect of drying after subjecting to various pre-
treatments on leaf and oil quality was also studied.
Neelamari leaves were harvested at 70 days after transplanting (DAT),
115 DAT and 160 DAT. At each stage of harvest, the yield and quality of fresh
leaves in terms of Relative Water Content (RWC), indican (Indoxyl β- D-
glucoside) the glucoside responsible for the colour, total sugar and tannin were
observed. The highest yield (48.05 g-1plant), was obtained when harvesting was
done at 160 DAT and at this stage leaves had highest tannin (1.78mg 100g-1),
total sugars (4.62%) and indican (1.23%) and it was significantly different from
other treatments. At each harvesting stage, the leaves were stored for 4, 8, 24
and 48 hours and observed for its quality in comparison with fresh leaves. The
freshly harvested leaves recorded higher value for indican (0.913%) but there
was no significant difference in tannin (1.307mg 100g-1) and total sugars
(4.70%). The interaction of cutting stage and storage showed significant effect
on leaf quality as indicated by the highest indican content (1.24%) in fresh
leaves harvested at 160 DAT and considering it as the best, was used for further
studies.
Three blanching methods including hot water, steam and microwave
blanching were compared with unblanched control, followed by shade, cabinet
and vacuum drying. The treated leaves were, analysed for indican content and
found that, microwave blanching for 45 seconds followed by vacuum drying at
35±5°C had highest retention of indican (3.045%).
Further Neelibhrngadi Taila was prepared using the decoctions of dried
leaf samples, along with fresh Neelamari leaf juice considered as control
treatment as per Ayurvedic Pharmacopeia of India (API). The samples of
Neelibhrngadi Taila prepared were subjected to quality assessment by
estimating acid value, refractive index and performing Thin Layer
Chromatography (TLC) with absolute control as the standard, as per the
recommendation of API, which defines well the quality check of the medicated
oils. Least acid value (1.460mg of KOH g-1 of sample) was a desirable feature
recorded in oil sample prepared using microwave blanched and vacuum dried
leaf samples and the highest acid value recorded was in the sample prepared
using hot water blanched cabinet dried leaves. There was no difference in the
refractive index as coconut oil was the common base oil in all the treatments
and it revealed the uniform extraction of phytochemicals in to the oil in all the
13 formulations. The results from TLC showed that all the oil samples except
those obtained from treatment T10 (steam blanched and dried in vacuum drier)
and T11 (Hot water blanched and dried in vacuum drier) gave standard Rf value,
thus conforming to the quality prescribed by API. In HPTLC performed using
absolute control as standard, all the samples recorded 13-17 peaks representing
different phytochemical compounds whereas the standard oil recorded 16 peaks.
Further studies are required to identify the phytochemical compounds.