Natural Products: Essential Resources for Drug Discovery

Professor SC Jain

Department of ChemistryUniversity of Delhi

Delhi, India

A Short History of Medicine

2000 B.C. ---- Here, eat this root.

1000 A.D. ---- That root is

heathen.

Here, say this prayer.

1850 A.D. ----That prayer is

superstition.

Here, drink this potion.

1940 A.D. ---- That potion is snake oil.

Here, swallow this pill.

1985 A.D. ----That pill is

ineffective.

Here, take this antibiotic.

2005 A.D. ---- That antibiotic doesn’t work anymore.

Here, eat this root….

Ancient MedicinesAncient Medicines

OAc

OOH

Extract of myrtle bark used for rheumatism and back pain. Salicin was isolated by Johann A Buchner in 1828. 3,500 years ago, Egyptian physicians advocated salicin in the form of herbal

preparation. Felix Hoffmann synthesized in 1897

Aspirin

Quinine

N

N

OHH

OMe

Extract of cinchona tree was used to treat malaria. Referred in Indian Vedic writing (3600 yrs ago) and in the prose of Hippocrates

(2,500 yrs ago). Robert B. Woodward synthesized in 1944.

Penicillin

N

Me

Me

NH

O

PhO

COOHO

Penicillin was discovered by Alexander Flemming in 1928. Penicillin antibiotics are the first drugs that were effective against syphilis and

Staphylococcus infections. It is a group of antibiotics derived from Penicillium notatum fungi

TaxolTaxol

O

OAc

OH

OAcOO

O

OO

OH

NH

O

HOH

Extracted from the bark and needles of the yew tree, Taxus brevifolia. Monroe E. Wall and Mansukh C. Wani identified Taxol in 1971. Taxol is one of the newer chemotherapy drugs, and in use. K C Nicolaou synthesized in 1994

Ecteinascidin

NH

O

O

N

O

O

CH3

O

O

S

OH

OCH3

OH

H HN

H

CH3

OCH3

OHH

CH3

H

New anticancer agent isolated from "the mangrove tunicate" (Ecteinascidia turbinata) found in the Florida.

This drug is in human trials for breast and ovarian cancers and is one of the most promising new treatment under development for solid tumors.

Bryostatin

O O O

O

O

OHO

O

O

O

O O

O

H

H OH

OH

OH

H

HOH

Product produced by a spiral bryozoan, Bugula californica, It is an exciting new form of chemotherapy as it selectively kills cancer cells without harming normal and healthy ones.

Expected to be shortly available as a new weapon against cancer.

Pseudopterosins

OHOH

O OH

OH

O

H

Present in carribean sea whip, Pseudopterogorgia elisabethae in Florida. Possess anti-inflammatory and analgesic properties (better than indomethacin).

0

50

100

150

200

mic

roorg

an

ism

s

gre

en

alg

ae

bro

wn

alg

ae

red

alg

ae

sp

on

ges

bry

ozo

an

s

mollu

scs

tun

icate

s

coele

nte

rate

s

ech

inod

erm

s

mis

cellan

eou

s

Phylum

Non-active

Active

Distribution of biologically active and non-activemarine natural products by phylum, 2003

spon

ges

020406080

100120

mic

roor

gan

ism

s

gree

n a

lgae

bro

wn

alg

ae

red

alg

ae

bry

ozoa

ns

mol

lusc

s

tun

icat

es

coel

ente

rate

s

ech

inod

erm

s

mis

cell

aneo

us

Phylum

AC

AM

IV

AO

Other

Distribution of biological activity by phylum. (AC- cancer related assays including cytotoxicity, antimiotic, histone deacetylase, proteasome, DNA binding and matrix metalloproteinase; AM- antimicrobial, antiinfective; AO- antimalarial assays; IV-in vivo assays such as brine shrimp and sea urchin eggs; Other- includes antiviral assays, assays based on central nervous system, feeding deterrent assays, ion channel assays, antifouling assays and assays for Fe siderophores and sperm attractant).

Naturally Occurring 3-alkyl/ alkenyl pyridine alkaloids

Source : Marine Sponges 37 Alkaloids known from various species Varied in chain length, number & position of unsaturation and

substitution in the side chain Possess various biological activities:

Cytotoxic Antileukaemic Antineoplastic Antimicrobial and  Antifungal

Strong calcium ion inducers (20 times more potent than Caffeine)

N. Fusetani et al, N. Fusetani et al, J. Nat. ProductJ. Nat. Product, , 20002000, , 6363, 682-684, 682-684

1.01.0AmphimedonAmphimedonHachijodine GHachijodine G

1.01.0AmphimedonAmphimedonHachijodine FHachijodine F

2.32.3AmphimedonAmphimedonHachijodine EHachijodine E

2.22.2XestospongiaXestospongiaHachijodine DHachijodine D

2.22.2XestospongiaXestospongiaHachijodine CHachijodine C

2.22.2XestospongiaXestospongiaHachijodine BHachijodine B

2.22.2XestospongiaXestospongiaHachijodine AHachijodine A

ICIC5050 Value ( Value (g/ml)g/ml)SpeciesSpeciesStructureStructureNameName

Cytotoxic alkaloids (P-388 Murine Leukemia cells)

N

N

Me

O

H

8

N

N O

H

11

N

Me

NO

H

9

NMe

NO

H

10

N

N

OH

11

N

N

OH

3

7

N

OH

N

7

NameName StructureStructure SpeciesSpecies ICIC5050 Value Value ( ( g/ml) g/ml)

Ikimine-AIkimine-A Niphates Sp.Niphates Sp. 1010

Ikimine-BIkimine-B Niphates Sp.Niphates Sp. 55

Ikimine-CIkimine-C Niphates Sp.Niphates Sp. 77

J. Kobayashi et al, J. Kobayashi et al, JCS. Perkin Trans-1JCS. Perkin Trans-1, , 19921992, 1291-94 , 1291-94 P.J. Scheuer et al, P.J. Scheuer et al, TetrahedronTetrahedron, , 19901990, , 4646, 6637-44, 6637-44

NO

N

9

N

N

O

8

ONH

N

11

Cytotoxic alkaloids ( KB cells)

-D-Glucosylated cytotoxic alkaloids ( P-388 murine leukemia cells)

NOHO

OHOH

N

OH OCH3

n

m

N

NOHO

OHOH

OCH3OH

Amphimedoside A : m = 3, n=9

Amphimedoside B : m = 3, n=7

Amphimedoside C : m = 1, n=9

Amphimedoside E

Nobuhiro Fusetani et al., American Chemical Society and American Society of Pharmacognosy, Published on Web 10/11/2006

Anti-microfouling alkaloids

NameName StructureStructure SpeciesSpecies ICIC5050 Value Value

((g/ml)g/ml)

Untenine AUntenine A CallyspongiaCallyspongia 3.03.0

Untenine BUntenine B CallyspongiaCallyspongia 3.03.0

Untenine CUntenine C CallyspongiaCallyspongia 6.16.1

Wang, G.Y.S., Kuramoto, M. and Uemura, D. Wang, G.Y.S., Kuramoto, M. and Uemura, D. Tetrahedron LettTetrahedron Lett., 1996, ., 1996, 37(11)37(11), 1813, 1813

N

NO2 8

NO2

N

8

N

NO2 8

Literature Method

(a) n-BuLi, THP, -400C(b) 3N HCl, MeOH(c) Swern oxidation(d) NH3 or MeNH2, MeOH, NaBH4

(e) Pd-C/H2, EtOH

Rao, A.V.R., Reddy, G.R. and Rao, B.V., J. Org. Chem., 1991, 56, 545-47.

N

OTHP Br Ph3P(CH2)11OTHP

N

OH

N

CHO

N

NH2

N

OTHP

O

N

H

N

OTHP

N

OH

N

CHO

N

NH2

Br Ph3P(CH2)10OTHP

9

9

8

8

11

11

10

9NH

N

9

9 NH

N

9

+

b

c

a

d

a

e

b

c

d

N

N

H

OCH3

NCH3

OHN

N

N

OH

CH3

N

N

OCH3

H

6

N

6 3

N

N

5 4

N NHOHn

N15

N

NO2

Hachijodine A

Hachijodine E

Ikimine C

Untenine B

Target Molecules

Retro Analysis

S

O

O O O Br N

N

H

N OCH3n

N

H

N OCH3n

SO2Ph

BrN

n

SO2Ph

OHN

n

SO2Ph

OTHPN

n

SO2Ph

+n

Synthon A Synthon B

Br-

N+

N+

N+

N+

N

CH3

N

COOH

N

CH2OH

N

COOCH3

N+

CH2Br

HBr

-N

CH2 S

O

O

4

a

b

c

a = NBS/CCl4/Benzoylperoxide

b = NBS/hv/CCl4/reflux 4 hrsc = NBS/AIBN/CCl4/reflux

a bc d

a = Abs. MeOH/conc. H2SO4

b = LAH/diethyletherc = aq.HBr/refluxd = C6H5SO2Na/DMF

Synthesis of Synthon A

Synthesis of Synthon B

OH OHn Br Br

n Br OH

n

O Brn Oa +

b

(i) n = 11(ii) n = 12

a = Hexane/aq.HBr/liq.liq. extractionb = DHP/H+

(i) n = 11(ii) n = 12

(i) n = 11(ii) n = 12

(i) n = 11(ii) n = 12

major

N

SO2Ph

O On N

SO2Ph

OHn

N

SO2Ph

Brn

N

OH

CH3N

SO2Ph

n

N

OCH3

HN

SO2Ph

n

O Brn O

NCH2 S

O

O

N

OCH3

HN

SO2Ph

n

N

SO2Ph

NO2 n

(i) n = 11(ii) n = 12

Hachijodine A

a = NaH/DMF/00C/r.t.b = pTsOH/MeOHc = aq.HBr/refluxd = NH2OCH3HCl/NaH/DMF/ reflux

e = NHOHCH3HCl/NaH/DMF/ reflux

f = 5% Na-Hg amalgam/abs ethanolg = NaNO2/MeOH/ reflux

S.C. J ain et al., Pure and Applied Chem., 2005, 77(1), 185

+a b

Coupling of Synthon A and B

(i) n = 11(ii) n = 12

c

(i) n = 11(ii) n = 12

Hachijodine E

n = 11

n = 12 n = 12

Ikimine C

d

fd

f

f

(i) n = 11(ii) n = 12

e

g

Untenine B

f

n = 11

N

SO2Ph

Br N

SO2Ph

NO2

N

SO2Ph

NHOH N NHOH

N

SO2Ph

Br NN

SO2Ph

CH3

OHN

CH3

OHN 11 11 11

9 9

910

N

SO2Ph

Br N

SO2Ph

N

O

O

1111 N

SO2Ph

NH2 11N NH2 12

N

SO2Ph

Br NN

SO2Ph

CH3

CH3

N

CH3

CH3N 11 11 11

a b

a = NHOHCH3HCl/NaH/DMFb = 5% Na-Hg amalgam/abs ethanolc = NaNO2/abs methanol/reflux

c d b

Synthesis of 3-alkylpyridine analogues

e

g b

d = Zn dust/NH4Cl/aq. ethanole = pthalimide/K2CO3/DMF/r.t.f = NH2NH2. H20/C2H5OH/refluxg = NH(CH3)2.HCl/ K2CO3/DMF/rt

f b

SO2Ph

RN RNS

O

ON

R X

Br

4 4 Br

3 6

Br

4

Br

a = 5% NaH/DMF/0 0C/r.t.b = Na-Hg amalgam/abs ethanol

a b+

R =

Some New Analogues by Molecular Modification

11R

N S

OO

11R

N S

OOCH3

+

I -

11

S

Br

OON11

S

Br

OON

O

+S

OON

R11

O-

+

11

S

Br

OON11

R

N S

OO

11

S

Br

OON

N O N S N N CH3 N N

-

R = , , , ,

a

a b

c a

a = K2CO3/DMF/rtb = CH3I/Acetone/rtc = mCPBA/DCM/rt

Some New Analogues by Molecular Modification

 Comparison of DNA, RNA and protein content in E. coli bacterial growth after the treatment with synthetic samples 

100* mean there is no inhibition in control samples.Values out of the bracket in green shows the amount in g.

Values in blue shows the total growth in percentValues in red shows the %growth inhibition

- means no significant inhibition was observed.

Compound code

DNA RNA Protein

Control 8.625 (100)* 3.25 (100)* 420 (100)*

PS1 4.375 (50.72)49.28 1.375 (42.3)57.70 110 (26.19)73.81

AP3 8.375 (97.10)2.90 2.25 (69.23)30.77 350 (83.33)16.67

AP5 2.25 (26.08)73.92 2.25 (69.23)30.77 240 (57.14)42.86

AP8 2.75 (31.88)68.12 1.79 (53.84)46.16 190 (45.23)54.77

AP9 2.5 (28.98) 71.02 1.125 (34.61)75.39 110 (26.19)73.81

AP10 1.875 (21.73)78.27 2.5 (76.92)23.08 210 (50)50.00

 Comparison of DNA, RNA and protein content in Bacillus cerus bacterial growth after the treatment with synthetic samples 

 100* mean there is no inhibition in control samples.

Values out of the bracket in green shows the amount in g.Values in blue shows the total growth in percent

Values in red shows the %growth inhibition- means no significant inhibition was observed.

Compound code

DNA RNA Protein

Control 3.25 (100)* 50.5 (100)* 1350 (100)*

PS1 0.4 (12.31)87.69 11.0 (21.78)78.22 240 (17.77)82.23

AP3 1.25 (38.46)61.54 14.5 (28.71)71.29 410 (30.37)69.63

AP5 1.0 (30.77)69.23 19.5 (38.61)61.39 260 (19.26)80.74

AP8 1.0 (30.77)69.23 16.0 (31.68)68.32 240 (17.77)82.23

AP9 1.6 (49.23)50.77 20.5 (40.59)59.41 250 (18.52)81.48

AP10 1.25 (38.46)61.54 11.0 (21.78)78.22 300 (22.22)77.78

  Comparison of DNA, RNA and protein content in Lactobacillus bacterial growth after the treatment with synthetic samples 

100* mean there is no inhibition in control samples.Values out of the bracket in green shows the amount in g.

Values in blue shows the total growth in percentValues in red shows the %growth inhibition

- means no significant inhibition was observed.

Compound code

DNA RNA Protein

Control 8.00(100)* 40.00(100)* 700(100)*

PS1 2.4(30)70.00 14.5(36.25)73.75 30(4.28)95.72

AP3 2.4(30)70.00 30.5(76.25)23.75 140(20)80.00

AP5 4.0(50)50.00 20.5(51.25)48.75 20(2.86)97.14

AP8 2.75(34.37)65.63 5.5(13.75)86.25 340(48.57)51.43

AP9 4.8(60)40.00 21(52.5)47.50 320(45.71)54.29

AP10 - 30.5(76.25)23.75 180(25.71)74.29

Compounds tested

N

SO2Ph

O O 6

Compound code Structure Mol. formula

PS1 C7H10NI

AP3 C6H7NO

AP5 C12H11NO2S

AP8 C23H31NO4S

AP9 C18H23NO3S

AP10 C18H22NO2SBr

N+

CH3

CH3

I -

N

CH2OH

NCH2 S

O

O

N

SO2Ph

OH 6

N

SO2Ph

Br 6

SampleCode

Conc.(μg/ml)

Gram positive bacteria Gram negative bacteria Fungi

S.aureus B.subtilis S.epidermis S.typhi E.coli K.pneumoniae A.niger A.fumigatus C.albicans

62 100 12 13 12 10 12 13 14 12 13

63 100 11 12 11 10 11 13 12 11 12

64 100 11 13 -- 11 11 12 11 10 11

65 100 12 14 15 12 10 14 16 12 16

67 100 12 10 14 11 10 12 15 12 12

69 100 10 10 -- 10 11 11 11 10 13

70 100 -- 10 10 10 12 10 13 10 11

71 100 10 11 11 -- 12 12 10 11 11

72 100 12 10 11 13 10 14 15 14 16

73 100 11 10 10 14 10 10 12 -- 12

74 100 13 -- 10 10 -- 11 12 10 12

75 100 12 11 -- 10 12 12 10 11 12

77 100 11 12 -- 11 11 10 10 10 10

78 100 12 -- 11 11 11 11 -- 11 11

79 100 11 11 -- 12 10 12 -- 10 10

Control Solvent -- -- -- -- -- -- -- -- --

Standard* 100 22 18 20 17 18 21 16 14 18

Antimicrobial Evaluation of Some More Synthetic Compounds

* Ciprofloxacin for bacteria and Miconazole for fungi; Cup-Plate method used

SYNTHESIS OF BIOLOGICALLY IMPORTANT PHENOLIC LIPIDS

15

158

8 11

15

8 11 14

11

817

8 11

17

1017

1219

21

13

8

813

11

13

17

14

8 11 1417

R

OH

COOH

R =

R =

R =

R =

R =

R =

R =

R =

R =

R =

R =

R =

R =

R =

R =

R =

(from Pistachia vera)

(from Anacardium giganeum) (from Anacardium occidentale)

(from Pentaspadon motleyic Hook)

(from Ginkgoales)

(from Spondias mombin)

(from Anacardium occidentale)

Some Naturally Occurring Non-isoprenoid Phenolic Acids

Non-isoprenoid phenolic acids possess:

(a) Antiviral Activity* Coxsackie B2

* Herpes simplexb) Antibacterial Activity (at 3-25 g/ml concentration) * Bacillus cereus * Streptococcus pyogenes * Mycobacterium fortuitum(c) Molluscicidal Activity (Lc90 down to 1-3 ppm) * Biomphalaria glabrata

Molluscicidal activity LCMolluscicidal activity LC5050 and LC and LC9090 values in ppm of some Non-isoprenoid values in ppm of some Non-isoprenoid phenolic acids (PA) isolated from phenolic acids (PA) isolated from Spondias mombin L.Spondias mombin L.

CompoundCompound LCLC5050 (ppm) (ppm) LCLC90 90 (ppm)(ppm)

(17:3) PA-1(17:3) PA-1 ± 1± 1 33

(17:2) PA-2(17:2) PA-2 ± 1± 1 33

(17:1) PA-3(17:1) PA-3 11 33

(19:1) PA-4(19:1) PA-4 66 66

(21:1) PA-5(21:1) PA-5 66 66

R

OH

COOH

8 11

17

1017

1219

21

8 11 1417

PA-1 R =

PA-2 R =

PA-3 R =

(from Spondias mombin)

PA-4 R =

PA-5 R =

OUR TARGET MOLECULEOUR TARGET MOLECULE

Problems encountered in direct synthesis

-OH group is ortho-para directing while –COOH group is meta directing, so difficult to carrya. direct alkylation or alkenylation at C-6b. direct hydroxylation at C-2

Difficult to carry direct carboxylation because of steric hindrance due to the presence of long alkyl or alkenyl chain and hydroxyl group at adjacent carbons.

R

OH

COOH

CH3

OH

CH3

CH3

CH3

OCH3

CH3

OCH3

CHO

CH3

OCH3

CH2OH

CH2Br

OCH3

COOCH3

CH3

OCH3

COOCH3

CH3

OCH3

COOH

OH

COOH

RCH2X

OH

COOH

+a b

c

de

(a) = (CH3)2SO4/K2CO3 (anhyd.)/Acetone (dry) (b) = K2S2O8/CuSO4.5H2O/Py/CH3CN/H2O(c) = KMnO4/Benzene/H2O(d) = CH2N2/Ether (dry) (e) = NBS/CCl4 (dry)

+

A B

Retro-Analysis

Synthesis of A

R-X

R = alkyl, alkenyl

65% 35%

Synthesis of Target Molecule

CH2Br

OCH3

COOCH3 PhSO2Na/DMF

CH2

OCH3

COOCH3

S

O

OLDA/dry THF/RX

CH

OCH3

COOCH3

SO2Ph

R

CH2

OCH3

COOCH3

S

O

O

n-BuLi/Dry THF/

CH

OCH3

COOCH3

SO2Ph

R

CH2

OCH3

COOCH3

S

O

O

NaH/Dry THF/

CH

OCH3

COOCH3

SO2Ph

R

OCH3

COOCH3

R

NaOH/DMSO,

OCH3

R

COOHBCl3/DCM

OH

R

COOH

-780C

10%

-780C

16%

RX

-100C

75%

RX

Na/Hg (5%)

70%

75%

-300C

95%

Coupling of A & B

OH

R

COOH

8

8

8 11

13

17

15

11

1710

1912

1521

7

7

8 15

17

10

19

OH

OH

OH

OH

13

OH

OH

COOH

COOH

11

17

17

19

19

21

1. R =

2. R =

3. R =

4. R =

5. R =

6. R =

7. R =

8. R =

9. R =

10. R =

11. R =

12. R =

13. R =

14. R =

15. R =

1 & 10 isolated from Anacardium occidentale and Anacardium giganteum2 & 3 isolated from Pistachia. vera and Anacardium occidentale5,6,8,9 isolated from Spondias mombinRest are unnatural analogues

16. R =

17. R =

18. R =

19. R =

20. R =

21. R =

22. R =

23. R =

24. R =

25. R =

26. R =

27. R =

28. R =

List of Compounds Synthesized

Molluscicidal activity:

Test compoundTest compound Concentration (ppm)Concentration (ppm) Molluscicidal activity Molluscicidal activity (% mortality) (% mortality)

SCJ-404SCJ-404 55 00

SCJ-405SCJ-405 55 1010

SCJ-406SCJ-406 55 1010

SCJ-407SCJ-407 55 9090

SCJ-408SCJ-408 55 8080

SCJ-411SCJ-411 55 4040

SCJ-412SCJ-412 55 00

Methodology: Sullivan et al., Planta Medica, 1982,44, 175-177. Corthout et al., Planta Medica, 1994, 60, 460-463.

From these preliminary experiments it can be concluded that molluscicidal activity is associated with an unsaturated side chain and that a double bond in position 12 of the side chain is better than in position 10. Both OCH3/COOH and OH/COOH substitution pattern show good activity.

Inhibition of Cyclooxygenase-1, Cyclooxygenase-2

Test compound (50 Test compound (50 g/ml)g/ml) COX-1 (% inhibition)COX-1 (% inhibition) COX-2 (% inhibition)COX-2 (% inhibition)

SCJ-404SCJ-404 85.2±5.385.2±5.3 93.9±1.393.9±1.3

SCJ-406SCJ-406 17.9±13.617.9±13.6 17.5±6.117.5±6.1

SCJ-407SCJ-407 83.5±7.283.5±7.2 73.1±6.173.1±6.1

SCJ-408SCJ-408 85.9±4.385.9±4.3 90.6±1.290.6±1.2

SCJ-412SCJ-412 88.3±2.288.3±2.2 85.0±3.185.0±3.1

Methodology: Redl K. et al., Planta Medica, 1994,60, 58-62. Reginer E. and Bauer R., 46th Annual Congress of the Society for Medicinal Plant Research, 31.09.98-04.09.98, Vienna (abstract)

Inhibition of Lipoxygenase

Test compoundTest compound LCLC5050 value ( value (g/ml)g/ml)

SCJ-404SCJ-404 6.256.25

SCJ-406SCJ-406 0.930.93

SCJ-407SCJ-407 2.732.73

SCJ-408SCJ-408 0.860.86

SCJ-412SCJ-412 6.206.20

Apparently compounds with a side chain unsaturated in position 12 are the most potent inhibitors of lipoxygenase. Further experiments to establish more detailed structure-activity relationships are in progress.

 Comparison of DNA, RNA and protein content in E. coli bacterial growth after the treatment with synthetic samples 

100* mean there is no inhibition in control samples.Values out of the bracket in green shows the amount in g.

Values in blue shows the total growth in percentValues in red shows the %growth inhibition

- means no significant inhibition was observed.

Compound code

DNA RNA Protein

Control 8.625 (100)* 3.25 (100)* 420 (100)*

SA14 2.7 (31.3)68.70 1.75 (53.84)46.16 160 (38.09)61.91

SA18 0.5(5.79)94.21 2.87 (88.30)11.70 320 (76.19)23.81

SA19 2.5 (28.98)71.02 2.0 (61.53)38.47 165 (39.28)60.72

SA20 5.37 (62.26)37.74 1.125 (34.61)65.39 270 (64.28)35.72

SA29 2.5 (28.98) 71.02 2.5 (76.92)23.08 140 (33.33)66.67

 Comparison of DNA, RNA and protein content in Bacillus cerus bacterial growth after the treatment with synthetic samples 

 100* mean there is no inhibition in control samples.

Values out of the bracket in green shows the amount in g.Values in blue shows the total growth in percent

Values in red shows the %growth inhibition- means no significant inhibition was observed.

Compound code

DNA RNA Protein

Control 3.25 (100)* 50.5 (100)* 1350 (100)*

SA14 2.4 (73.85)26.15 4.5 (8.91)91.19 160 (11.85)88.15

SA18 2.4 (73.85)26.15 10.5 (20.79)79.21 300 (22.22)77.78

SA19 1.6 9(49.23)50.77 10.5 (20.79)79.21 160 (11.85)88.15

SA20 1.6 (49.23)50.77 40.5 (28.71)71.29 230 (17.04)82.96

SA29 0.4 (12.31)87.69 21.00(41.58)58.42 420 (31.11)68.89

  Comparison of DNA, RNA and protein content in Lactobacillus bacterial growth after the treatment with synthetic samples 

100* mean there is no inhibition in control samples.Values out of the bracket in green shows the amount in g.

Values in blue shows the total growth in percentValues in red shows the %growth inhibition

- means no significant inhibition was observed.

Compound code

DNA RNA Protein

Control 8.00(100)* 40.00(100)* 700(100)*

SA14 8.0(100)00.00 - 400(57.14)42.86

SA18 1.25(15.62)18.38 32.5(81.25)18.75 460(66.71)33.29

SA19 1.0(12.5)87.5 21(52.5)47.5 160(22.86)77.14

SA20 - - 110(15.71)84.29

SA29 4.0(50)50.00 29.5(73.75)26.25 100(14.28)85.72

Compound code Structure Mol. formula

SA14 C19H23NO5S

SA18 C22H27O5SBr

SA19 C22H27O7NS

SA20 C22H29NO6S

SA29 C24H32O6S

SO2Ph

NH2

OCH3

COOCH3

3

SO2Ph

Br

OCH3

COOCH3

6

SO2Ph

OCH3

COOCH3

NO26

SO2Ph

OCH3

COOCH3

NHOH6

SO2Ph

OCH3

COOCH3

OH8

Compounds tested

SYNTHESIS OF 6-ALKYL/ALKENYL AMINO ACIDSSYNTHESIS OF 6-ALKYL/ALKENYL AMINO ACIDS

Used as herbicides to weeds including Digitaria sanguinalis, Rumex obtusifolius, Sorghum halepense, Imperata cylindrica, Parricum spp. and Paspalurn spp.

N-Acyl derivatives inhibited the growth of blue grass algae. Increases frost resistance in wheat, tobacco, corn and grape plants. Used for increasing sugar contents in sugar cane. Possesses both pre-emergent and post-emergent plant growth regulant

activity. The post-emergent activity is most significant that control weeds by reducing their vigor and competitiveness and, thus prevent their spread and stop normal seeding

NH2

COOH

CH3

6-Methyl Anthranilic Acid

OUR TARGET MOLECULEOUR TARGET MOLECULE

NH2

COOH

R

R = alkyl, alkenyl

CH3

NH2

CH3

NHCOCH3

CH3

NHCOCH3

NO2

CH3

NHCOCH3

O2N

CH3

NO2

CN

CH3

N+

NO2

NCl

CH3

NO2

COOH

CH3

NH2

NO2

CH2Br

COOCH3

NO2

CH3

COOCH3

NO2

NO2

COOCH3

SO O

NH2

COOH

RCH2X

NO2

COOCH3

+a b c

-f e

d

g

(a) (CH3CO)2O; (b) Fuming HNO3/Glacial CH3COOH(c) Dilute HCl; (d) NaNO2/HCl; (e) CuCN/KCN(f) 70%H2SO4/1200C; (g) CH2N2/ether (dry);(h) NBS/CCl4; (i) PhSO2Na/DMF

i

h

RETRO-ANALYSIS

Synthesis of A:

+ R-X

R = alkyl, alkenyl

A B

30% 70%

S

NO2

COOCH3

O O SO2Ph

NO2

COOCH3

n n

NH2

COOH

n

NH2

COOCH3

n

HNCH3

COOCH3

n

HNCOCH3

COOH

n

HNCOCH3

COOCH3

A

RBr

a n = 3b n = 4c n = 6d n = 8e n = 16

+B C

D D

A = NaH/THF/-100C; B = 10% Na-Hg/EtOH; C = CH2N2/ether (dry); D = Ac2O

a n = 5b n = 6c n = 8d n = 10e n = 18

a n = 5b n = 6c n = 8d n = 10e n = 18

a n = 5b n = 6c n = 8d n = 10e n = 18

a n = 5b n = 6c n = 8d n = 10e n = 18

a n = 5b n = 6c n = 8d n = 10e n = 18

NH2

R

COOH

1. R =

2. R =

3. R =

4. R =

5. R =

6. R =

7. R =

8. R =

9. R =

List of Amino Acids Synthesized

ConclusionsConclusions

Developed a new and convenient route for the synthesis of 6-alkyl/alkenyl salicylic acids, 3-alkylpyridines and 2-amino-6-alkyl/alkenyl benzoic acids using sulphone as potent intermediates.

Confirmed the structures of 8 naturally occurring 6-alkyl/alkenyl salicylic acids and 4 cytotoxic pyridine alkaloids.

Antibacterial activity decreases with an increase in carbon chain length and with decrease in number of unsaturation.

6-Alkenyl salicylic acids with three unsaturation are found to be more active than the di- or mono- unsaturated compounds.

Unsaturated 6-alkenyl-salicylic acids are the most potent naturally occurring molluscicides.

3-Alkylpyridines and their analogues possessed very strong cytotoxic activity against p-388 murine leukemia cells with IC50 values of 1-2.3g/ml

Some of the synthetic analogues of 3-alkylpyridines have also been evaluated for their antibaterial properties against E. coli, Bacillus cereus and Lactobacillus and the findings are encouraging.

Some of the 3-alkylpyridine analogues have been recently also found to posses cytotoxic activity for lung, breast, prostate and ovary cancer.

In all 44 6-alkyl/alkenyl salicylic acids, 52 amino acids and 4 naturally occurring pyridine alkaloids along with 15 synthetic analogues have been successfully synthesised in search for a suitable drug candidate.

ACKNOWLEDGMENTSACKNOWLEDGMENTS

Dr. Rohtash Kumar Dr. Rajeev Goswami Dr. Mukesh Kumar Pandey Dr. Shilpi Khurana Mr Amit K Srivastava Mr.Siva S Panda Prof L Pieters (Belgium) Prof A Vlietinck (Belgium)

&

Funding agencies

Council of Scientific and Industrial Research and University Grant Commission (New Delhi)