678
abundant amount among all the compounds in the lipophilic extract was sterols with
β-sitosterol and stigmasterol with the concentration of 67–80% (wt). The leaves and
stalk contained higher amount of stigmasterol with 13.45% and 15.15%, respectively, while flowers had β-sitosterol in abundant quantity. Extract from leaves
(4.86 mg AAE /g biomass (mg ascorbic acid equivalent per gram biomass)) has exhibited
better antioxidant action compared to the extracts obtained from stalks and roots,
i.e. 2.04 mg AAE /g biomass and 0.11 mg AAE /g biomass , respectively. Among all the parts,
leaves possessed the highest value of phenolic compounds followed by the stalks
and roots.
The total phenolic compounds (TPC) have been extracted from petioles, leaves
and flowers by Surendraraj et al. [44]. The biomass was extracted with 96% ethanol
as well as distilled water at room temperature overnight. The extraction yield with
water was found more as compared to ethanol. The highest extraction yield of
25.5% (wt) was obtained for flowers with water. Phenolic contents of various sections of water hyacinth were in the range of 0.84–6.66 mg GAE /g of dried sample.
TPC have been obtained in a higher amount in flowers compared to other parts of
the plant. The ethanolic extract of Eichhornia crassipes showed the presence of
α-tocopherol in significant amount in petioles, δ- tocopherol in leaves and
γ-tocopherol in petioles. A total of 11 phenolic acids were identified from the water
and ethanolic extract such as benzoic phenolic types (gallic, protocatechuic, gentisic, p-hydroxybenzoic, vanillic and salicylic acid) and cinnamic phenolic types
(chlorogenic, syringic, caffeic, p-coumaric and ferulic acid). Protocatechuic and
gentisic acids have been found in greater amount in ethanolic extract of petioles,
leaves and flowers. Flowers have a significant amount of protocatechuic acid
(53.94 mg/g extract) and gentisic acid (137.26 mg/g extract) [44]
Recovery of shikimic acid in purer form from the aerial parts and roots was carried out using methanol and water as solvents. The techniques are used for extraction such as magnetic stirring and sonication at room temperature as well as 45 °C
and Soxhlet extraction. The maximum yield of shikimic acid (1.45%) and (2.70%)
was obtained for aerial part of water hyacinth using sonication at room temperature
and Soxhlet extraction, respectively [43].
4.2 Water Hyacinth as a Source of Sorbent for Heavy Metals
and Dyes
Aquatic plants can control the pollution caused due to heavy metals and pesticides
in freshwater. Since the conditions are favourable in tropical and subtropical regions,
Eichhornia crassipes is produced in huge quantity and has gained importance for
this purpose. Apart from adsorbing or accumulating heavy metals, water hyacinth is
capable of converting reactively toxic compounds to inert and nontoxic compounds
[46]. Powder and adsorbents made from various parts of this plant have been
assessed for removal of harmful compounds. Different parameters such as
P. V. Ganorkar et al.
abundant amount among all the compounds in the lipophilic extract was sterols with
β-sitosterol and stigmasterol with the concentration of 67–80% (wt). The leaves and
stalk contained higher amount of stigmasterol with 13.45% and 15.15%, respectively, while flowers had β-sitosterol in abundant quantity. Extract from leaves
(4.86 mg AAE /g biomass (mg ascorbic acid equivalent per gram biomass)) has exhibited
better antioxidant action compared to the extracts obtained from stalks and roots,
i.e. 2.04 mg AAE /g biomass and 0.11 mg AAE /g biomass , respectively. Among all the parts,
leaves possessed the highest value of phenolic compounds followed by the stalks
and roots.
The total phenolic compounds (TPC) have been extracted from petioles, leaves
and flowers by Surendraraj et al. [44]. The biomass was extracted with 96% ethanol
as well as distilled water at room temperature overnight. The extraction yield with
water was found more as compared to ethanol. The highest extraction yield of
25.5% (wt) was obtained for flowers with water. Phenolic contents of various sections of water hyacinth were in the range of 0.84–6.66 mg GAE /g of dried sample.
TPC have been obtained in a higher amount in flowers compared to other parts of
the plant. The ethanolic extract of Eichhornia crassipes showed the presence of
α-tocopherol in significant amount in petioles, δ- tocopherol in leaves and
γ-tocopherol in petioles. A total of 11 phenolic acids were identified from the water
and ethanolic extract such as benzoic phenolic types (gallic, protocatechuic, gentisic, p-hydroxybenzoic, vanillic and salicylic acid) and cinnamic phenolic types
(chlorogenic, syringic, caffeic, p-coumaric and ferulic acid). Protocatechuic and
gentisic acids have been found in greater amount in ethanolic extract of petioles,
leaves and flowers. Flowers have a significant amount of protocatechuic acid
(53.94 mg/g extract) and gentisic acid (137.26 mg/g extract) [44]
Recovery of shikimic acid in purer form from the aerial parts and roots was carried out using methanol and water as solvents. The techniques are used for extraction such as magnetic stirring and sonication at room temperature as well as 45 °C
and Soxhlet extraction. The maximum yield of shikimic acid (1.45%) and (2.70%)
was obtained for aerial part of water hyacinth using sonication at room temperature
and Soxhlet extraction, respectively [43].
4.2 Water Hyacinth as a Source of Sorbent for Heavy Metals
and Dyes
Aquatic plants can control the pollution caused due to heavy metals and pesticides
in freshwater. Since the conditions are favourable in tropical and subtropical regions,
Eichhornia crassipes is produced in huge quantity and has gained importance for
this purpose. Apart from adsorbing or accumulating heavy metals, water hyacinth is
capable of converting reactively toxic compounds to inert and nontoxic compounds
[46]. Powder and adsorbents made from various parts of this plant have been
assessed for removal of harmful compounds. Different parameters such as
P. V. Ganorkar et al.