STUDIES ON BIOACTIVITY IN SOME SEAWEEDS FROM KARACHI COAST

Plant derived natural products are extremely important as sources of medicinal agents and used as model for thtYdesign, synthesis and semi-synthesis of novel substances for treating humankind's diseases. In this present study, 28 seaweed species belonging to 19 genera namely Colpomenia siYiuosa, Dictyo!a dichotoma, D. dichotoma var. indica, Iyengaria stellata, Padina pavonia, Sargassum binderi, S. obvatum, S. swartzit, S. tenerrimum, S. variegatum, S. wightit, Spatoglossum asperum, S. variabile, Stoechospermum marginatum, Stokeyia indica (Brown); Caulerpa racemosa, C. taxifolia, Codium iyengarit, Halimeda tuna, Rhizoclonium implexum, Viva Jasiam, u. lactuca, (Green) Botryocladia leptopoda, Halymenia porphyroides, Jania capillacea, Malanothamnus somalensis, Sciania indica and Solieria robusta (Red) were collected from Buleji beach, Paradise point and New Nithya gali, coastal areas of Karachi and identified.Ethanolic extracts of thirteen seaweed species Botryocladia leptopoda, Caulerpa racemosa, Colpomenia sinuosa, lyengaria stellata, Pad.na pavonia, Sargassum binderi, S. swartzit, S. vlriabile, Seiania indica, Spatoglossllm asperum, Solierio robusta, Stoechospermum morginatum and Stokeyia indica @ 10 mg/200g body weight were tested for their hypolipidaemic activity. Most of the test species significantly decreased the serum total cholesterol, triglycerides and low density lipoprotein cholesterol levels in different rat models. B. leptopoda, C. racemosa, C. sinuosa, 1. stellata, P. pavonia, S. asperum, S. indica and S. robusta have profound effect on lipid prof Ie. Seven species of seaweeds B. leptopoda, C. racemosa, C. sinllosa, 1. stellata, S. indica, S. asperum an1 S. robusta which showed significant results in normal rats were also tested in triton-induced and high fat diet-induced hyperlipidaemic rats. In tritoninduced hyperlipidaemic rats, all the test seaweeds showed significant lowering effect on total cholesterol, triglyceride and low density lipoprotein cholesterol as compared to triton-induced hyperlipidaemic control rats. Feeding of the extracts @ 10 mg /200 g b.WI. dail~' for 12 days in animals maintained on high fat diet showed decrease in lipid and low density lipoprotein cholesterol with subsequent significant increase in high density lipoprotein cholesterol in rats treated with all seaweeds. Treatment of rats maintained on high fat diet with S. asperum also demonstrated significant decrease in cardiac and liver enzymes like lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and serum glutamate oxaloacetate-transaminase (SGOT/ASAT). Solieria robusta was found most effeclive in reducing tile lipid profile particularly in high fat diet-induced hyperlipidaemic rats. Two oily fractions isolated from ethanolic extract of Spatoglossum asperum, named as SA-IV and SA-VI were found a mixture of fait)' acid esters ideutified on the basis of gas liquid mass spectroscopy (GC-l\IS). These fractions showed significant hypolipidaemic activity in normal, triton and high fat diet-induced hyperlipidaemic rats with a significant increase in HDL-c in normal and high fat diet-induced ltyperlipidaemic rats. Both th, fractions showed significant lowering effect on serum enzymes like LDH, ALP, ASAT and ALAT. GC-MS of fraction SA-IV isolated from S.asperum showed the presence of methyl esters of saturated fatty acids (methyl-ntetradccanoate, C'f4:0; methyl-n-hexadecanoate, CI6:0; methyl-n-octadecanoate, CI8:0); methyl esters of unsaturated fatty acid (methyl-trans-octadecen-2..oate, CI8:1) and ethyl ester of fatty acid (ethyl-nhexadecanoate). Fraction SA-VI showed presence of methyl esters of saturated fatty acids (methyl-nn heptanoate, C7:0; methyl-n-tetradecanoate, C 14:0; methyl-n-hexadecanoate, CI6:0;' methyl-n-heptadecanoic acid, CI7:0) and methyl esters of unsaturated fatty acid (methyl-trans-octadec-9,12 dienoate, CI8:2: and methyl-cis, cis-octadec -9,12-die'1oate. This is first time report ofhypolipidaemic activity of seaweeds from Karachi coast.The search for cancer chemotherapeutic natural products has been rapidly accelerating in recent years. The cytotoxicity of plant material is considered as the presence of antitumour compounds. The ethanolic extract of 22 seaweed species (13 brown, 6 green and 3 red) were investigated for brine shrimp c\10toxicity. Six species (5 brown and I green) Caulerpa racemosa, Sargassum binderi, S.swartzii, Spatoglossum asperum, Stoechospermum marginatum, and Sfokeyia indica showed significant activity (LC" value below \000 ",glml). Cytotoxicity ofthese 6 species were further tested in the hexane, ethylacetate and methanol soluble fraction of their ethanolic extract as well as in the water extract. The nhexane soluble fractions of ethanolie extract of Sfoechospermllm marginatllm and Sargassum swartzii were found more effective. Whereas methanol soluble fractions of Spafoglossllm asperum and Sargassum binderi werc found active. Water extract of S. indica and C. recemosa showed LC,o value below 70 ",glm!. The results suggest that cytotoxic activity may be due to the compounds differ on the basis of polarity.Since antiquity human being are searching drugs from plants, active against infectious diseases and parasites. In the present study ethanolic extracts of 22 seaweed species (5 green, 13 brown and 4 red) belonging to 16 genera were tested for antibacterial activity. Codium iyengarii, Spafoglossum asperum and S. variabile inhibited all the six test bacteria viz.. SfaphylococclI., aureus, Bacillus subfilis, Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa and Agrobacterium tumefaciens and produced zone of inhibitions. Callierpa fa'ifolia, Iyengaria .Plants with antagonistic properties oner ar alternate for hazardous synthetic pesticides for the management of -pla"t pathogens. In this study out of 17 seaweed species tested against root infecting fungi viz., Macrophomina phaseolina, Rhizoctonia so/ani, Fusarium so/ani and F. or;ysporum. Two species Spatog/ossum asperum and S. variabi/e inhibited the radial gro\\1h of M. phaseolina, R. so/ani and F. so/ani i" vitro when used @ 6mg/disc. S. marginatum and C. iyengarii also inhibited the growth of F. so/ani on the same concentration. Methanol and ethyl-acetate soluble tractions of S. asperum were found active against M.l'haseolina, while its n-hexane fraction showed activity against .1. so/ani. Ethyl-aceta~ fraction of S. "ariabi/e inhibited M. phaseolina and F. so/ani while its methanol soluble fraction inhibited only F. so/ani. Ethyl-acetate fraction of S. marginalum inhibited F. so/ani and F. oxysporum and methanol fraction showed activity against F. so/ani. Oily fraction isolated from S. asperum and named as SA-IV showed strong antibacterial and antifungal activities.Plant parasitic nematodes constitute one of the most important and destructive pest group of economIC crops both in developed and under-developed countries, causing huge losses. iOthanolic extracts of 23 seaweeds species were tested for nematicidal activity against Me/oidogyne javanica root knot nematode juveniles. Sargassum binderi, Slokeyia indica. Cau/eI1JC1laxi(olia, Codilln7 iyengarii and Rhizoc/onium imp/exum caused hundred percent mortali'y after 48 hours @ 10 mg/ml. Stokeyia indica. Sargassum swartzll anu Solie ria robusta caused more than 50 % mortality at dose level of I mg/ml. nHexane fractions of Spatog/ossum asperum, S. indica and C. iyengarii as well as methanol soluble fraction of S. asperum and chloroform fraction of S. swartzii produced more than 90 % mortality of nematodes @ 10 mg/ml after 48 hours. Of the oily fractions of S. asperum tested, SA-V showed maximum nematicidal activity. Fraction SA- V was found to contain methyl esters of saturated fatty acids (methyl-n-tetradecanoate, CI4:0; methyl-n-pentadecanoate, CI5:0; methyl-n-hexadecanoate. CI6:0); methyl ester of unsaturated fatty acid (methyl-trans-octadecen-2-oate, CI8:1) and ethyl ester of fatty acid (ethyl-n-hexadecanoate, CI6:0).Utilization of seaweeds in farming "' extended hundreds of years ago, since they contain equal nitrogen and greater potash than fann yard manure with antagonistic activity against some plant pathogens. Soil amendment with Sargassum tenerrimum, S. swartzii and S wightii with or without biocontrol agents viz., Paeci/omyces lilacinus, Pseudomonas aeruginosa and Bradyrhizobium japonicum, significantly (P<0.05) reduced Me/oidogyne javanica, root knot nematode infection in okra roots. Use of S. swartzii and S. wightii showed significant control of Fusarium so/ani and Macrophomina phaseolina infection used alone or with P. lilacinus, B. japonicum and P. aeruginosa. Stokeyia indica, Iycngaria stellata (brown) and S. robusta (red) seaweeds showed significant (pApplication of chemical pesticides and fertilizers fcr the management of plant diseases and growth is back bone of modem agriculture. Seaweeds Spatog/ossum aspen'm and Sargassum swarlzii used alone or with chemical fertilizer such as urea and potash, showed significant control of root infecting fungi Macrophomina phaseolina, Rhizoctonia so/ani, Fusarium so/ani and root knot nematode Me/oidogyne javanica. A combined use of seaweed with urea or potash resnlted in better plant growth than either used alone. Efficacy of seaweeds S. asperum and S. swartzii was also compared with benlate. captan (fungicide) and furadan (nematicide). Seaweed showed more or less similar effect in reducing the infection of root infecting fungi and root knot nematode on okra and tomato as commercial pesticides. Seaweeds showed better growth of tomato plant when used with furadan, a nematicide.Caulerpin, an indol alkaloid isolated and purified from Cau/erpa racemosa and its crystal structure (dimethyl-6, 13-dihydro-dibenzo-[b,i]-pl'enazine.5, 12-dicarboxylate), C,.JI1,N,O. has been reported in space group Cc with an acute f3 ,ngle was re-determined in the correct space group, C21eA crystalline compound isolated and purified by column chromatography of SpatogiosslIm asperum was also ch:lracterized as caulerpin on the basis of spectroscopic data recorded like UV. IR. 'H. I3C-NMR and Mass. Caulerpin is first time reported f"om the brown seaweed S. asperum. In vitro test caulerpin showed weak nematicidal activity against root knot nematode and strong activity against Macrophomina phaseolina, a charcoal rot fungus which attack more than five hundred plant species.